Archive:Article of the Week

The Article of the Week is an article chosen by vote among Citizens as exemplifying various qualities we like to see in a Citizendium article; see our article standards.

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Table of Nominees

Nominated article	Supporters	Specialist supporters	Score
Milpa agriculture	Milton Beychok 00:15, 29 May 2009 (UTC); Arne Eickenberg 14:15, 17 June 2009 (UTC); Peter Schmitt 23:23, 24 June 2009 (UTC)		3
The Canterbury Tales	Milton Beychok 03:04, 7 July 2009 (UTC); Meg Ireland 05:06, 7 July 2009 (UTC);		2
Domain Name System	Peter Schmitt 00:14, 8 July 2009 (UTC); Howard C. Berkowitz 15:55, 8 July 2009 (UTC)		2

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The next article (or draft) of the week will be the article with the most votes at 1 AM UTC on Thursday, 16 July 2009. The honors were done this time by Milton Beychok.

Text in this section is transcluded from the respective Citizendium entries and may change when these are edited.

Nominated article	Supporters	Specialist supporters	Score
Milpa agriculture: A form of swidden agriculture that is practiced in Mesoamerica. Traditionally, a "milpa" plot is planted with maize, beans, and squash. [e] The metadata subpage is missing. You can start it via filling in this form or by following the instructions that come up after clicking on the [show] link to the right. Do you see this on PREVIEW? then SAVE! before following a link. To find out more about the use of metadata for the management of Citizendium pages, see CZ:Metadata. You may see this box for one of two reasons. Either: A - New page has been created, or subpages template was added to an existing page B - Cluster move is in progress Click either the A or B link for further instructions. [Feel free to recommend improvements to the text or links in this template] A - For a New Cluster use the following directions Subpages format requires a metadata page. Using the following instructions will complete the process of creating this article's subpages. Click the blue "metadata template" link below to create the page. On the edit page that appears paste in the article's title across from "pagename =". You might also fill out the checklist part of the form. Ignore the rest. For background, see Using the Subpages template Don't worry--you'll get the hang of it right away. Remember to hit Save! the "metadata template". However, you can create articles without subpages. Just delete the {{subpages}} template from the top of this page and this prompt will disappear. :) Don't feel obligated to use subpages, it's more important that you write sentences, which you can always do without writing fancy code. [Feel free to recommend improvements to the text or links in this template] B - For a Cluster Move use the following directions The metadata template should be moved to the new name as the first step. Please revert this move and start by using the Move Cluster link at the top left of the talk page. The name prior to this move can be found at the following link. [Feel free to recommend improvements to the text or links in this template] (CC) Photo: Joey Hipolito Milpa plots are found from Chihuahua to Central America. This one is in Oaxaca, Mexico. Squashes are being grown between the rows of maize. Milpa agriculture is a form of swidden agriculture that is practiced in Mesoamerica. Traditionally, a "milpa" plot (from the Nahuatl word for "corn field") is planted with maize, beans, and squash (known as the Three Sisters) and might include a variety of other plants. These plots are planted for two or three years and then allowed to lie fallow for some years in order to restore the fertility of the soil. Milpa agriculture varies somewhat by region and it has changed in a variety of ways in different areas but it remains an important part of life for millions of people throughout Mesoamerica. Maize and beans Maize and beans, which are the staples of the Mesoamerican diet, complement each other in terms of the health of the fields as well as the health of the people who eat them. Maize requires high levels of nitrogen in the soil to grow properly and quickly depletes the soil if planted alone. Bean plants (genus Phaseolus), on the other hand, are high in nitrogen and their presence extends the life of the maize plot significantly by helping to keep nitrogen levels healthy. One might say that the maize repays the debt it owes to the beans by providing stalks for the bean plants to cling to as they grow. Squashes, generally grown between the rows of maize stalks, also figure into this symbiotic relationship, as they cover the ground in between the rows of corn and help to keep weeds down. Maize and beans also compliment each other nutritionally. If eaten alone, one would need to consume large amounts to fulfill human dietary requirements but when eaten together, they achieve "protein complimentarity." That is to say, a person needs less total food if the two are eaten together. This diet is further supplemented by several varieties of squash and other foods that are planted along side the maize and beans. In many areas, the "Mesoamerican trio" (maize, beans and squash) is complemented by wild or semi-domesticated plants that grow in and around the milpa. (CC) Photo: Lorena Pajares Harvesting beans from a mountainside milpa in Chiapas, Mexico. Planting and harvesting Milpas are traditionally cultivated using the swidden, or "slash and burn" system. The forest is cut, allowed to dry and then burned. The left over ashes are then mixed into the soil as a fertilizer. Maize and beans are planted together in the same hole while squash is planted separately, in between the rows of maize. Other cultigens may be planted in a separate section of the field or scattered among the maize. The fields must be weeded several times throughout out the season. This is backbreaking work, especially in areas where a milpa is likely to be planted on the slope of a mountain several hours walk from home and it is usually done mostly by hand with the help of machetes and hoes. Later in the season, weeding is less needed, as the broad leaves of the squash plants keep unwanted plants to a minimum and the maize grows out of reach of the weeds. Beans and squash are harvested as they ripen. As the maize ripens, a few elotes (or fresh cobs) may be picked to be eaten right away but most of the plants are bent near the top and the cobs are allowed to dry in the field. Once they are dry, they are collected and stored for later use in traditional Mesoamerican foods like tortillas and tamales. The dry stalks are often collected and sold at market as fodder for animals and the husks are frequently saved for use in preparing tamales. The weeds and left over corn stalks from the previous season will be burned to prepare the fields for planting for one or two more years but then they will be left to fallow for as much as ten or more years. This practice has been abandoned in many areas because of the shortage of land that is available to many families. Instead, animal dung or ashes from the hearth at home may be added to those mixed into the soil and many farmers have turned to industrial fertilizers that allow them to cultivate the same plot year after year. The ritual life of the milpa One of many ornate murals in the Zapatista community of Oventic in Chiapas, Mexico. One need not look far to discover the intimate connection between maize and people in Mesoamerican culture. Here, a human head wearing the characteristic Zapatista ski mask appears on every kernel. Several important rituals are performed at key points during the growing season. The timing of these rituals varies by region and altitude due to variations in climate and the length of the growing season but they are invariably tied to significant events in the ritual calendar. Among the Maya, agricultural rituals are performed at the full moon while in central Mexico, each ceremony is associated with one of the eighteen months in the solar calendar and occur at periods of twenty days. Ceremonies are performed at each major stage in the development of the maize, beginning with the planting and concluding with the harvest. Agricultural rituals also vary in form according to local traditions, but common themes are found throughout Mesoamerica. One such theme is the ritual reenactment of the creation of the world by marking the four cardinal directions. Among the K'iche' of highland Guatemala, offerings are made at the four corners of the milpa. The Kekchi plant maize in the center of the field first and then plant in each of the fours directions. In Tepotzlán, the Nahuas place crosses made from pericón at the four corners of the field. And in the Sierra Madre of northern Mexico, the Tarahumara open their work parties by scattering tesguino, or corn beer, to the four directions. Other themes include sacrifices and offerings to indigenous deities or Catholic saints and prayers for rain. Maize also figures prominently in ritual activities that are not directly connected to the cultivation of the milpa. In Amatlán, Nahua villagers say, "Corn is our blood," meaning, "corn defines our way of life" in everything from ethnic identity to every day activities. In fact, the Popul Vuh reveals that the first mothers and fathers of the Maya were actually formed from maize. Maize, and especially the intimate connection between maize and humans, arises again and again in both ancient and modern myths. Modern trends One consequence of the changes in land ownership patterns introduced through Spanish colonial society and some of the agrarian reforms carried out by the modern states in the region is that many families do not own enough land to produce all of the food that they need in a year. Consequently, the practice of fallowing the fields has disappeared or nearly disappeared in many areas. Today, many farmers use chemical fertilizers to increase their fields’ production and engage in other economic activities to earn enough money to provide for their families. Even when farmers have access to enough land to feed their own families, they are often unable to market their surplus. Trade liberalization and market deregulation policies adopted throughout the region in the 1980s and 1990s have meant that maize and other staple crops produced on a very large scale by U.S. corporations are frequently available at lower prices in local markets than the products of local farmers. Thus, many farmers have also converted their fields to other crops. Today, cash crops destined for export to the U.S. include broccoli, snow peas, cucumbers, Brussels sprouts, and carnations. Despite the market pressures felt by small scale farmers in Mesoamerica to turn away from traditional agriculture, milpas may hold information that can help improve modern agricultural methods. Monocrop agriculture creates artificial growing conditions that are significantly less biologically diverse than the natural ecosystems that they replace. This results in rapid depletion of the soil, which is generally counteracted by the application of chemical fertilizers that return nutrients to the soil but may have damaging effects in the long-term. Though it is unlikely that the balancing diversity of milpa agriculture can be reproduced on an industrial scale, the indigenous knowledge embedded in its design may provide some guidelines for improving industrial techniques. "By studying [the milpa's] essential features," writes Charles C. Mann, "researchers may be able to smooth the rough ecological edges of conventional agriculture." Notes  (Read more...)	Milton Beychok 00:15, 29 May 2009 (UTC); Arne Eickenberg 14:15, 17 June 2009 (UTC); Peter Schmitt 23:23, 24 June 2009 (UTC);		3
The Canterbury Tales: Collection of stories in verse and prose by Geoffrey Chaucer. [e] The metadata subpage is missing. You can start it via filling in this form or by following the instructions that come up after clicking on the [show] link to the right. Do you see this on PREVIEW? then SAVE! before following a link. To find out more about the use of metadata for the management of Citizendium pages, see CZ:Metadata. You may see this box for one of two reasons. Either: A - New page has been created, or subpages template was added to an existing page B - Cluster move is in progress Click either the A or B link for further instructions. [Feel free to recommend improvements to the text or links in this template] A - For a New Cluster use the following directions Subpages format requires a metadata page. Using the following instructions will complete the process of creating this article's subpages. Click the blue "metadata template" link below to create the page. 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[Feel free to recommend improvements to the text or links in this template] Canterbury Tales Woodcut 1484 The Canterbury Tales is a collection of tales written by Geoffrey Chaucer between 1387 and 1400, two of them in prose, the rest in verse. The tales, some of which are originals and others not, are contained inside a frame tale and told by a group of pilgrims on their way from Southwark to Canterbury to visit the shrine of Saint Thomas Becket at Canterbury Cathedral. The Canterbury Tales are remarkable for having been written in the vernacular, Middle English, rather than the language of courtiers (French) or of the church (Latin). From the earliest days of their appearance to the present moment, they have been recognized as a foundational pillar of English literature. The Oxford English Dictionary says that "in later times" the phrase "Canterbury Tale" is "often taken as" being "a long tedious story, a fable, a cock-and-bull story". Poetic structure Much of The Canterbury Tales is in iambic pentameters with an AABB rhyming scheme, but a few tales were written in other forms, among them the ballad stanza. The individual tales The themes of the tales vary, and include topics such as courtly love, treachery, and avarice. The genres also vary, and include romance, Breton lai, sermon, beast fable, and fabliau. The characters, introduced in the General Prologue of the book, tell tales of great cultural relevance. The Tales include: The General Prologue The Knight's Tale The Miller's Prologue and Tale The Reeve's Prologue and Tale The Cook's Prologue and Tale The Man of Law's Prologue and Tale The Wife of Bath's Prologue and Tale The Friar's Prologue and Tale The Summoner's Prologue and Tale The Clerk's Prologue and Tale The Merchant's Prologue and Tale The Squire's Prologue and Tale The Franklin's Prologue and Tale The Physician's Tale The Pardoner's Prologue and Tale The Shipman's Tale The Prioress' Prologue and Tale Chaucer's Tale of Sir Topas The Tale of Melibee The Monk's Prologue and Tale The Nun's Priest's Prologue and Tale The Second Nun's Prologue and Tale The Canon's Yeoman's Prologue and Tale The Manciple's Prologue and Tale The Parson's Prologue and Tale Chaucer's Retraction Some of the tales are serious and others humorous; however, all are very precise in describing the traits and faults of human nature. Antifraternal and anti-clerical themes abound, along with instances of courtly romance, fabliaux, and the traditional ballad. The work is incomplete, at least if we take at face value the claim in the General Prologue that each character would tell four tales, two on the way to Canterbury and two on the return journey. This would have meant a possible one hundred and twenty tales which would have dwarfed the twenty-six tales actually written. The missing tales inspired many, some quite soon after Chaucer's death in 1400, to write their own additional tales, among them the spurious Plowman's Tale and the Tale of Beryn, a continuation of the narrative which includes the pilgrims' eventual arrival in Canterbury itself as well as the beginning of the return journey. From the 14th century to the present, readers have found political overtones within the tales, particularly as Chaucer himself was a significant courtier and political figure at the time, close to the corridors of power. Chaucer's wife Philippa (de) Roet was the sister of John of Gaunt's favourite mistress (afterwards third wife), Katherine Swynford, and Chaucer had close ties with the so-called Lollard Knights. There are many hints at contemporary events, although few are proven, and the theme of marriage common in the tales is presumed to allude to several different marriages, most often those of John of Gaunt. In addition to Chaucer himself, Harry Bailly of the Tabard Inn was a real person and the Cook has been identified as quite likely to be Roger Knight de Ware, a contemporary London, United Kingdom cook. The complete work The work was probably begun in the 1380s with Chaucer stopping work at some point in the late 1390s prior to his death in 1400. It was not written down fully conceived: it seems to have had many revisions with the addition of new tales at various times. The plan for one hundred and twenty tales is from the general prologue. It is announced by Harry Bailly, the host, that there will be four tales each. This is not necessarily the opinion of Chaucer himself, who appears as the only character to tell more than one tale. It has been suggested that the unfinished state was deliberate on Chaucer's part. The structure of The Canterbury Tales is a frame narrative and easy to find in other contemporary works, such as The Book of Good Love by Juan Ruiz and Boccaccio's Decameron, which may have been one of Chaucer's main sources of inspiration. Chaucer indeed adapted several of Boccaccio's stories to put in the mouths of his own pilgrims, but what sets Chaucer's work apart from his contemporaries' is his characters. Compared to Boccaccio's main characters - seven women and three men, all young, fresh and well-to-do, and given Classical names - the characters in Chaucer are of extremely varied stock, including representatives of most of the branches of the middle classes at that time. Not only are the participants very different, but they tell very different types of tales, with their personalities showing through both in their choices of tales and in the way they tell them. The idea of a pilgrimage appears to have been mainly a useful device to get such a diverse collection of people together for literary purposes. The Monk would probably not be allowed to undertake the pilgrimage and some of the other characters would be unlikely ever to want to attend. Also all of the pilgrims ride horses, there is no suggestion of them suffering for their religion. None of the popular shrines along the way are visited and there is no suggestion that anyone attends mass, so that it seems much more like a tourist's jaunt. Chaucer does not pay that much attention to the progress of the trip. He hints that the tales take several days but he does not detail any overnight stays. Although the journey could be done in one day this speed would make telling tales difficult and three to four days was the usual duration for such pilgrimages. The 18th of April is mentioned in the tales and Walter William Skeat, a 19th-century editor, determined 17 April 1387 as the probable first day of the tales. Scholars divide the tales into ten fragments. The tales that make up a fragment are directly connected, usually with one character speaking to and handing over to another character, but there is no connection between most of the other fragments. This means that there are several possible permutations for the order of the fragments and consequently the tales themselves. The above listing is perhaps the most common in modern times, with the fragments numbered I-X, but an alternative order lists them A-G, with the tales from the Physician's until the Nun's Priest's placed before the Wife of Bath's. The exception to the independence between fragments are the last two. The Manciple's tale is the last tale in IX but fragment X starts with the Parson's prologue by saying that the Manciple had finished his tale. The reason that they are kept as two different fragments is that the Manciple starts his short tale in the morning but the Parson's tale is told at four in the afternoon. It is assumed that Chaucer would have amended his manuscript or inserted more tales to fill the time. Two early manuscripts of the tale are the Hengwrt Chaucer manuscript and the Ellesmere manuscript. Altogether, the Tales survives in eighty-four manuscripts and four printed editions dating from before 1500. The Canterbury Tales Project is transcribing the whole text of all these versions, comparing them to attempt to uncover how they are related, and publishing transcripts, images and analyses of all this: see further the links in References, below. Significance Like Dante, Chaucer's greatest contribution that this work made to English literature was in popularising the literary use of the vernacular language, English (rather than French or Latin). Some of Chaucer's contemporaries, such as John Gower, also wrote some of their literary output in English, and yet only Chaucer staked his all on English, while at the same time taking inspiration from continental writers in the vernacular, such as Dante and Boccaccio. Within the tradition of English verse, Chaucer's output helped to assure the predominance of continental verse forms, in particular rhymed verse, over the traditional alliterative form. The pilgrims' route and real locations The pilgrims would probably have travelled along Watling Street, a route ancient even in Chaucer's time. Used by the Celts, paved by the Romans and named by the Anglo-Saxons, the stretch from London to Canterbury and then Dover is now the A2 road. The City of Canterbury has a museum dedicated to The Canterbury Tales". The postulated return journey has intrigued many and continuations have been written as well as tales written for the characters who are mentioned but not given a chance to speak. The Tale of Beryn is a story by an anonymous author within a 15th-century manuscript of the work. The tales are rearranged and there are some interludes in Canterbury, which they had finally reached, and Beryn is the first tale on the return journey, told by the Merchant. John Lydgate's Siege of Thebes is also a depiction of the return journey but the tales themselves are actually prequels to the tale of classical origin told by the Knight in Chaucer's work. Miscellanea The title of the work has become an everyday phrase in the language and has been variously adapted and adopted. Recently an animated version of some of the tales has been produced for British television. As well as a version with Modern English dialogue, there were versions in the original Middle English and Welsh. Evolutionist Richard Dawkins used The Canterbury Tales as a structure for his 2004 book about evolution - The Ancestor's Tale: A Pilgrimage to the Dawn of Evolution. His animal pilgrims are on their way to find the common ancestor, each telling a tale about evolution. In the U.S., The Canterbury Tales has been expurgated since its first appearance; it was subjected to revisions as late as 1928. In 1995, the book was challenged at Eureka Illinois High School for its lewd content and banned. Idries Shah in The Sufis wrote of evidence that the work was based on Fariduddin Attar's 12th-century work The Parliament Of The Birds citing various similarities between the two works. Like Attar, Chaucer had thirty participants in his pilgrimage and both works are an allegory of inner development. "The Pardoner's Tale" occurs in Attar's work, whilst the pear-tree story is found in Book IV of the Mathnawi by the 13th century author Rumi. Stage and film adaptations and allusions 1944 Powell and Pressburger, A Canterbury Tale (opening scenes) 1972 Pasolini, The Canterbury Tales 2004, BBC [1] 2005, Royal Shakespeare Company 2001, "A Knight's Tale" Notes  (Read more...)	Milton Beychok 03:35, 7 July 2009 (UTC); Meg Ireland 05:06, 7 July 2009 (UTC)		2
Domain Name System: The Internet service which translates to and from IP addresses and domain names. [e] The metadata subpage is missing. You can start it via filling in this form or by following the instructions that come up after clicking on the [show] link to the right. Do you see this on PREVIEW? then SAVE! before following a link. To find out more about the use of metadata for the management of Citizendium pages, see CZ:Metadata. You may see this box for one of two reasons. Either: A - New page has been created, or subpages template was added to an existing page B - Cluster move is in progress Click either the A or B link for further instructions. [Feel free to recommend improvements to the text or links in this template] A - For a New Cluster use the following directions Subpages format requires a metadata page. Using the following instructions will complete the process of creating this article's subpages. Click the blue "metadata template" link below to create the page. On the edit page that appears paste in the article's title across from "pagename =". You might also fill out the checklist part of the form. Ignore the rest. For background, see Using the Subpages template Don't worry--you'll get the hang of it right away. Remember to hit Save! the "metadata template". However, you can create articles without subpages. Just delete the {{subpages}} template from the top of this page and this prompt will disappear. :) Don't feel obligated to use subpages, it's more important that you write sentences, which you can always do without writing fancy code. [Feel free to recommend improvements to the text or links in this template] B - For a Cluster Move use the following directions The metadata template should be moved to the new name as the first step. Please revert this move and start by using the Move Cluster link at the top left of the talk page. The name prior to this move can be found at the following link. [Feel free to recommend improvements to the text or links in this template] On the Internet, the Domain Name System (DNS) is a critically important directory service that translates to and from a raw IP address (such as 207.46.197.32) and a domain name (such as microsoft.com). This allows people to interact with software via domain names, which are easier to remember than numerical IP addresses. More importantly, it allows computer-friendly but user-unfriendly IP addresses to change without affecting human users. Thus people can still expect to find the same information behind the user-friendly domain names, and need not be concerned if Microsoft Corporation changes the IP address on one of its host computers, as the domain name microsoft.com is sufficient, thanks to DNS, to find their computers regardless of which IP address the Microsoft administrator has assigned to those hosts. DNS is a hierarchical federated database, distributed widely across many host computers on the public Internet, and it also has a set of application protocols for interacting with the database. DNS names must comply with standards on the public Internet, but need not do so in a private internet where DNS is still useful. The original purpose of DNS was to translate a domain name to an IP address (forward DNS), and an IP address to a domain name (reverse DNS), but in recent years there have been ongoing attempts to expand the purpose and functionality of DNS in the public Internet. Further, because the lookup process for DNS superficially appears to resemble the lookup process for searching on the world wide web, it has become easy to confuse the purposes of a DNS lookup with a search-engine lookup. These two kinds of lookups have very different goals and occur at vastly different levels within the internet protocol stack. This article will explain the functions and purposes of the Domain Name System, the nature of its distributed and hierarchical database, and the protocols for accessing it. It will also note how the functions of DNS differ markedly from those of search engines, since this seems to be a matter of frequent confusion on the part of learners. In lay terms, you might think of DNS as like the white pages in a traditional phone book, and search engines as more like the yellow pages. As the white page type lookup service of the public Internet, DNS has been attacked by hostile programs either attempting to disrupt Internet traffic or divert users to illicit host machines. The distributed and simplistic approach taken by DNS has proved, historically, surprisingly resilient against such attacks, but as the size and importance of the public Internet has grown, so have the security concerns related to DNS. This article, or its related sub-articles, will also address basic DNS security issues. History DNS was first introduced for use on the Internet in 1983, with the first specification written by Paul Mockapetris. Mockapetris' first DNS implementation was called JEEVES, and replaced the ARPANET (pre-Internet) environment with few enough computers that a single file, hosts.txt, was sufficient to contain all connected computer names and their numeric addresses. Its designers, however, did not think of it as anything like a search engine, with the ability to seek a name corresponding to an idea (e.g. "pizza"), but to work with explicit names already known by the application. Manually maintaining and sharing host files became impractical as the scale of the Internet grew, and DNS was designed and implemented as the solution to the problem of scalable host name resolution. Note well: all DNS was designed to do was replace the hosts.txt file that had the name to address mappings for every computer in the ARPANET. That's all. DNS was not designed to be a search engine. Search engines hadn't been invented, since, after all, the Web had not been invented. Original design goals for DNS Protocol designers Name & address authorities System administrators Standard formats for resource data. Addresses for the root servers The definition of zone boundaries Standard methods for querying the database Unique assignments of domain names Master files of data (i.e., sets of Resource Records (RR) Standard methods for name servers to refresh local data from foreign name servers. Operation, perhaps with delegation of the root servers and top-level domain servers Statements of the refresh policies desired New requirements DNS security responsibilities Over the years, it has taken on more technical and administrative roles. These include providing additional information for the names and addresses, especially for security; the DNS infrastructure itself needed to be enhanced to be secure and trusted. DNS originally was manually configured, but there have been a variety of extensions to allow dynamic operation, such as the temporary binding of an address to a name. The domain name space, as well as the address spaces both for Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6), are under the authority of the Internet Corporation for Assigned Names and Numbers (ICANN), with much delegation of administration. The original system only handled IPv4, so one of the first steps for IPv6 support was defining how to represent IPv6 addresses in DNS. Berkeley Internet Name Domain (BIND), first deployed in BSD 4.3 UNIX and written by Kevin Dunlap, was the first widespread DNS implementation. BIND is now public domain code supported by the Internet Software Consortium In the years DNS has served, Internet technology and operational issues changed. When the new IPv6 address format came into use, the need to change name-to-address mapping tools to handle that format is understandable. Less obvious, but still necessary, is the new requirement to have a capability to track dynamically assigned addresses when there is no central address server. Domain Name System dynamic update can do such tracking, but dynamic update at this level is a security vulnerability. Address assignment spoofing is, by no means, the only threat to DNS, and an entire set of Domain Name System security (DNSSEC) extensions are being deployed. The U.S. government now requires DNSSEC for all Federal information systems, effective December 2009. Domain name structure and schema Domain Name System tree section The DNS namespace is hierarchical. Individual domain and host names within it have a textual representation, from right to left, which mirrors the tree that makes up the schema of the DNS: en.citizendium.com appears to have three components, but actually has four. The naming hierarchy is a tree, with increasingly specific levels reading right to left. From what can be seen in the textual example, .org is a top-level domain (TLD) under the authority of a TLD registry. .citizendium is a second-level domain under the authority of a SLD registry (SLD) .en identifies either a subdomain or a host, as defined by the citizendium.com technical administrator. What cannot be seen is the hierarchically "zeroth" highest part, the root. If a part usually suppressed were displayed, en.citizendium.com. The rightmost dot identifies the root of the DNS tree. In actual practice, there are multiple root servers, for which addresses are in an explicit file, a representative of which is found at http://www.internic.net/zones/named.root It is defined as: This file holds the information on root name servers needed to initialize cache of Internet domain name servers (e.g. reference this file in the "cache . <file>" configuration file of BIND domain name servers). A fully qualified domain name can be traced from the hierarchically lowest host name to the root. For example, en.citizendium.org goes from the host en all the way up to the top-level domain .org, which is connected to the root. A computer within the second-level domain citizendium.org could refer to the subdomain en, which would be a relative domain name; most DNS applications would append the current domain to the right of the host name. k12.en.citizendium.org is a hypothetical subdomain of en.citizendium.org; an arbitrary host could be larry.en.citizendium.org and the DNS software would understand if it is dealing with a host or a domain. Domain name authority and issues Name assignment The administrative process of DNS name assignment involves both DNS registries and DNS registrars DNS registries See also: Domain Name System non-technical policy issues DNS registries' fundamental role is to operate the data base for their top-level domain (TLD), and authorize registrars as "retail" agents to provide customer service. The bulk of TLDs are national, and use International Organization for Standardization (ISO) two-letter country codes (e.g., Canada = .ca, China = .cn, Germany = .de). In the majority of cases these country codes must be from the ISO 3166-1 list. However, there have been a few exceptions, usually for historical reasons. For example the ISO 3166-1 code for the United Kingdom is gb, but for historical reasons the assigned TLD is .uk. While the .gb TLD does exist, it has only one subdomain and does not accept new registrations. A few country codes, such as Tuvalu's .tv, form attractive branding, and the country has few internal registrants but considerable income from outside registrants. New TLDs are created by the Internet Corporation for Assigned Names and Numbers (ICANN), who then delegates the registry function to an organization that contracts with ICANN. Some new or proposed TLDs have been quite controversial, such as the .xxx domain for pornography. Others, which offer some competitive commercial service, may take much time and effort to create, since multiple organizations may want to be the registry. Remember that the public Internet, while international from the start, began as a U.S. project. A small set of non-national TLDs were created for early convenience. Country codes were not, at first, used, and the majority of registrations still go into the best-known .com. While the ".cc" country codes had gradually been used, they were formalized in the 1998 U.S. Department of Commerce White Paper about moving the U.S. government out of Internet operations. Some countries have a rational system where they use the "traditional" major suffix, or a variant of it, as a second-level domain, such as .co.uk, or .ac.uk. This, however, has not always been done in an intuitive or consistent manner. A relatively naive user might expect .com.uk to be correct in line with the international .com, but .co.uk is in fact correct. Based on this the user may then think that .or.uk would be the equivalent of .org, but in this case .org.uk is correct. Similarly one would expect that either .edu.uk or .ed.uk would correspond to .edu. But neither of these are correct, and instead .ac.uk is used for higher education colleges and universities, and .sch.uk for primary and secondary schools. Representative non-national TLD registries Top-level domain Registry Comments .aero Société Internationale de Télécommunications Aéronautiques SC, (SITA) Sponsored by air transport industry .com Verisign Unsponsored .edu Educause Under U.S. government agreement, ending in 2011 .net Verisign Unsponsored .mil Defense Information Systems Agency U.S. government agency .org Public Interest Registry (PIR) Unsponsored; not-for-profit .biz NeuLevel, Inc. Unsponsored There is a continuing business, political, and technical argument about the desirability of more TLDs, especially from those that want TLDs that are suggestive of the business purpose of a registrant. From a technical standpoint, while a proliferation of TLDs would not, as once suspected, seriously impact DNS performance, it would be likely to increase customer support cost due to the likelihood of making mistakes and getting the wrong domain. There are also legal issues of intellectual property involved in domain disputes. DNS registrars Registrars are the "retail" side of DNS operation. In .com and many other TLDs, they are profit-making entities. They deal with organizations that wish to acquire particular domain names, verifying the name is available, and then handling the administrative interaction with the domain registry. Most registrars are reasonable and ethical. They may be subdivisions of companies that can sell additional services, such as web server hosting, to domain registrants. Frequently, they have user support functions that will help new DNS administrators set up their zone files, or they may actually operate name servers on behalf of registrants. If there is a dispute over the rights to a domain name, one's registrar can be a valuable ally. There are registrars that compete for the business of large hosting centers and other organizations that need many domain names, typically discounting the registration fee to multiple-domain customers. It is to the advantage of a registrar to keep its existing customers, as most domains will be renewed, producing a continuing income stream. Registrars want to avoid "churn", a name for customers changing to other registrars. Some registrars, unfortunately, act against the original Internet tradition of it being a shared resource, and DNS being a service. Domain registrations expire annually, although one can pay the registrar to renew it automatically. It is not uncommon for certain registrars to look for domain names that expire in the near term, domains that were registered by a different registrar, and send the domain administrators what appear to be legitimate renewal notices. If completed and returned with payment, such a registrar will indeed renew the domain name — but transfer it away from the existing registrar. Legal and business issues associated with domain names When the ARPANET, and then the Internet, were new, DNS was seen as a simple mechanism to avoid memorizing or typing host addresses. As the Internet became more commercial, domain names acquired business value, since new users were apt to look for "company" at company.com. Indeed, as unpleasant to the DNS-knowledgeable ear as it may be, there are a substantial number of enterprises that have "dot-com", or sometimes other TLDs, as part of their corporate name. Another argument, the details of which involve intellectual property issues beyond the scope of this article, is the legal theory that a trademark must be "defended" or risks going into the public domain. If a second-level domain is identical to a trademarked company name, does the company have exclusive rights to it? Intellectual property attorneys have often argued that a well-known-company is not "defending" its trademark if it allows a domain to be created with its name, so there has been a tendency that whenever some TLD ".new" is created, trademark holders rush to register "well-known-company.new". Speculators, meanwhile, rush to do so before the trademark holder can do so, and, if successful, sell the rights to the domain at a very high price. One especially hotly argued issue is whether sexually-oriented businesses should have a .xxx TLD; some of those arguing for it also want to restrict access to sexually-oriented content, which would be identified by the TLD. Obviously, there would be no way to enforce keeping sexually-oriented content in .xxx, but it could reasonably be assumed that, if a domain were in .xxx, it was sexually-oriented. After six years of debate the .xxx TLD was approved in June 2010, and is expected to be launched in early 2011. Name servers and zone files One of the most confusing things to newcomers to DNS is the difference between a domain and a zone. One way to look at it is that a domain declares a range of potential names, while the zone defines the names actually in use. Formally, a [sub]domain is a namespace that need not have names in it. The basic source of name information that goes into a particular space is a zone file, created manually or with software assistance. Let us consider citizendium.org, which could have every valid character string as a subdomain from the shortened aaaa.citizendium.org to zzzz.citizendium.org. That are domains, comparable to the Citizendium name spaces such as Main, Talk, User, and CZ, in the sense that, ignoring lengths, the Main or Talk userspaces can have articles from Aaaa to Zzzz. Not all those article names, however, are meaningful. If, however, there are only actual hosts named en.citizendium.org, test.citizendium.org, reid.citizendium.org, and locke.citizendium.org, Citizendium's zone file would have only four host entries. To continue the analogy with CZ name spaces, the name file would be the set of articles, in each name space, which actually exist. Main: Zzzz is not an article; Main: Zero is an article. Populating a primary name server Just as the DNS namespace is a tree of domains, the actual information in that namespace can be regarded as a tree of zone files. Name servers are computers that contain information about domains, all the way up to the root. Be sure to understand the difference between the abstraction of a domain or subdomain namespace, and the zone file that describes the contents of that namespace and actually runs in a name server. The primary name server is authoritative for domains, and contains the master copy of the zone file for that domain. Name servers can contain more than one zone file; indeed, this is the usual case when there are domains with subdomains. Depending on the implementation, a name server may cache information in addition to what it learned from the zone file. For example, a local cache file in a name server could contain data about name-address relationships outside the domain, but which have been needed by a client within that domain. The name server may also contain limited-lifetime dynamic name updates, which might or might not be accessible from outside the domain. RFC1034, the basic DNS conceptual specification, describes two ways, one optional and one required, for looking up names. The same logic is relevant inside a domain that has caching nameservers. Iterative: the server refers the client to another server and lets the client pursue the query; the client is aware of multiple nameservers but is only interacting with one at a time Recursive: the first server pursues the query for the client at another server; the client is aware of only one DNS server Domains versus zones At each of the levels of the DNS hierarchy — top-level, second level, etc. — is an abstract namespace. No other second-level domain could have notcz.citizendium.org, but the administrator of citizendium.org is not obligated to have any number of subordinate hosts or domains. There is a subtle distinction between the abstraction of a name space, and a zone file that actually defines the hosts and subdomains in the zone. Name spaces define possible records; zone files contain actual records within that space, plus a few special cases such as "glue" records to name servers outside that space. wikipedia.citizendium.org is part of the citizendium.org namespace, but, since there is no such host, it is not in any zone file. Resource records Zone files are made up of resource records (RR). All RRs have several common properties: owner: the domain in which the authoritative RR resides. This is often implicitly derived from context, perhaps relative to the current domain name type: an encoded 16 bit value that defines the type of resource defined by the current records. Some types are obsolete, while others continue to be added for new DNS functions. class: an obsolete but required field, it is a 16 bit value for the protocol family with which the RR is associated. The only value used is the "Internet", textually represented as IN time to live: commonly called TTL, this parameter specifies how long the RR may be kept in a cache and assumed to be valid. It is a 32 bit integer, whose value is measured in seconds RDATA: type-specific data about the resource While there are many graphic tools for creating RRs, the basic textual syntax is: [owner] IN [class] [rdata] For example, the RR defining the address associated with the name XX.LCS.MIT.EDU XX.LCS.MIT.EDU. IN A 10.0.0.44 RR types in current use Class RR Name Function Typical RDATA SOA Start Of Authority Defines the start of a zone or a subzone; subordinate records inherit parameters Multiple fields A Address IPv4 Specifies the IPv4 address for a host IPv4 Address AAAA Address IPv6 Specifies the IPv6 address for a host IPv6 Address PTR "Pointer" Reverse mapping of address to name Name CNAME Canonical name Specifies an alias name for an address Address NS Name server (usually) An address of a name server one level of domain hierarchy above the current domain Address MX Mail exchanger Defines the start of a zone or a subzone; subordinate records inherit parameters A 16 bit preference value (lower is better) followed by a host name willing to act as a mail exchange for the owner domain. Wildcards in Resource Records An additional complexity of RRs is that they may contain wildcards. The simplest example is a " * " character that will match any string in a name expression. In specific situations, this is an extremely useful function, but it can complicate troubleshooting. In 2003, Verisign, who operates the .com registry, inserted a wildcard into the master DNS files, so that an undefined name, rather than returning an error message, would be redirected to one of the registry's commercial search engines. If the World Wide Web alone were the only function on the Internet, this might, although revenue-generating, have been useful. Unfortunately, there are many other functions on the Internet. In particular, messaging application protocols such as the Simple Mail Transfer Protocol (SMTP) would use the "host not found" information to conclude that mail to that host was undeliverable. A quite useful use for a wildcard, however, would be in a split DNS application, with different name resolution policies on different sides of a firewall. On the public Internet side of the firewall, the DNS server for example.com would have explicit records for the organization's public web server, mail server, and other public servers. Any reference to "inside" addresses, however, would be handled by the record: *.example.com IN A [outside address of the firewall] Domain Name System security, however, does not have a complete solution to working with wildcarded RRs. Deploying DNS To understand basic DNS, assume that it is being used in a single organization, which has one technical and administrative authority in control. In other words, the domain and its subdomains are homogeneous. While there may be minor exceptions due to the existence of temporarily cached data in individual clients and servers, and not all clients and servers may be able to view all parts of the highest-level domain, a single organization's DNS is essentially a distributed database, where there are multiple copies of a single "golden copy" of information. Once one starts interconnecting domains under different authority, as in the Internet, both administrative and technical aspects change. First, it is understood that while the total collection of all domains conceptually have access to all public name information, no single domain will have a copy of all information. Rather than being a distributed data base, it has become a federated data base, where there is a common indexing and retrieval model, but requests may need to go to multiple servers, in multiple domains and subdomains, before the request is satisfied. Second, even between well-recognized business partner organizations, there are trust issues. Third, there are miscreants actively attacking the DNS, for reasons from ideology to technical status to pure criminal revenue. Basic Implementation The administrator of a homogeneous domain (and its subdomains) starts by building a zone file that defines the names and addresses of hosts in that zone, optional additional information to be added to the responses, and to a higher-level nameserver that helps connect the domain of the zone to other domains. For example, if one was in a.com , one would have to go to the nameserver of .com to find the address of the b.com nameserver. SOA Resource Record The zone/domain name starts the record; it must end with a trailing period. Assume that it is sub.example.com. In the resource data, the first field is the primary name server that is in this domain, as opposed to the name server in the NS record, which is above and outside the current domain. In this case, it might be ns1.sub.example.com. Next comes the mail address of the person or role responsible for the data in this domain, written not in the conventional user@domain, but in the syntax of a DNS name in a zone file. To create a mail address, replace the leftmost period with an "@" symbol and remove the trailing period. " administrator.sub.example.com. " is changed to " administrator@sub.example.com ". Following the administrator are several parameters that may have defaults, but should be known. The first is the serial number of this version of the zone file, which will increase whenever this file is updated. The next four are timers for the domain, specified in seconds: refresh interval: Secondary name servers in the domain should check the primary for new data after this number of seconds expires retryinterval: If the secondary was unable to get an update when the refresh interval expires, this parameter tells the secondary how long to wait before retrying. The value in this field is usually less than the refresh interval expireinterval: If the secondary was unable to get an update before this timer expires, it should assume that all of the RR information is in its copy of the zone file. If this timer triggers, the secondary server will stop responding to DNS requests TTL: The default TTL for RRs in this zone. An appropriate TTL is controversial, and may be quite different on an internal nameserver versus one accessible from the Internet. The shorter the interval, the more accurate is the data, and, further, the better it is for name-based load distribution schemes. The longer the interval, the less DNS traffic is generated Other Resource Records NS gives the IP address of a hierarchically higher name server to which the name server goes when it cannot complete a name-to-address or address-to-name mapping based on its own information. A and AAAA code the authoritative host name and its address, and, optionally, the TTL if different from the zone TTL. PTR code an address and the corresponding host name, and, optionally, the TTL if different from the zone TTL. CNAME code an alternative host name and its address, and, optionally, the TTL if different from the zone TTL. Resource Record sets (RRsets) While no two RRs should have the same label and type and data all equal, it is perfectly possible to have RRs with the same label and type, but different RDATA. For example, a physically multihomed server could have four network interface cards (NIC), each on a different subnet. The set of addresses for this host name (i.e., label) would reasonably form a set of four A records with different address data. Such a set of records is called a Resource Record Set (RRSet). Obtaining root information The root name server zone file is expected to be retrieved, by anonymous FTP, from various well-known sites approved by ICANN. In practice, most DNS implementations ship with a recent copy. Root servers remain very busy. In fact, while the root server zone file mentioned above will give the names and addresses of root servers in the general form a.root-servers.net the address of a particular server is of the anycast type; there are multiple physical computers with that address, for fault tolerance and load sharing. For each domain, there must be at least one, and preferably more than one name server that holds the zone files. Primary domain servers have the authoritative zone files, and secondary domain servers keep an exact copy of the primary's zone file. Both types are assumed to have a disk or other storage from which they can restore the domain information. Zone transfer adds to populating a server database A secondary server will use a zone transfer to obtain the primary zone file for its domain. There are various operational reasons why a physical server might act as primary and secondary for multiple zones; the important point here is that a zone transfer, as opposed to ordinary DNS retrieval, alters the contents of the definitions and must be treated as a sensitive operation. Adding trusted dynamic updates The nameserver also can take dynamic transfers, which, strictly speaking, do not have to be secured, but dynamic update, especially in an IPv6 environment, is so open an invitation to miscreants that it should never be considered without being secured. DNS security is the normal way this might be done, but there are other alternatives, such as an encrypted link between the update source and the nameserver. There are also caching-only servers that contain only the names and addresses that have been recently looked up, and are still valid with respect to the TTL parameter in the relevant records. Resolvers, their caches, and their information sources The program, on a host, which is the client of DNS servers is most often called a resolver. Depending on the local network architectural implementation, a resolver may go to a caching-only server, a secondary server, or the primary server for its information. It may retain a cache of recently retrieved DNS information, clearing items from cache as their TTLs expire. Heterogeneous DNS While there will be different federated databases, DNS is certainly not limited to the public Internet. It is quite common for organizations to have split DNS "inside the firewall" and "outside the firewall". An inside user will query local DNS for the address of an internal machine and get the address of the actual host, but, if it asks for the address of citizendium.com, the address returned by DNS may well be that of the "inside" interface of a firewall, or other security middlebox Depending on the firewall implementation, it may deny access, or create a proxy connection to the outside host. To establish that connection, the middlebox will query an "outside" DNS, which contains the addresses of the organization's public hosts, but primarily contains the addresses of external hosts. In some cases, that outside DNS enjoys some trust with an external organization, and may do secured zone transfers. More often, however, the outside DNS is primarily a cache of name-address information that it obtained by queries to the nameservers of other domains. DNS protocols The most basic DNS protocols are the lookup service, which runs over port 53 of the connectionless User Datagram Protocol, and the zone transfer service, which also runs over port 53 of the connection-oriented Transmission Control Protocol. Lookup is a read-only function, while zone update is read-write and should be implemented as a privileged, authenticated operation. Otherwise any client on a DNS server's network could request a zone transfer, and receive a complete copy of a zonefile, which is a security risk. There are also protocols for dynamic update, so that network clients can automatically update their DNS servers to reflect correct hostnames (e.g. if they dynamically receive a different IP address via DHCP). This concept is also known as Dynamic DNS. Extended applications These include Domain Name System dynamic update, use of the DNS as a data base in Public Key Infrastructure (PKI) for general security, Domain Name System security (DNSSEC) and name-based routing and load distribution. References  (Read more...)	Peter Schmitt 00:14, 8 July 2009 (UTC); Howard C. Berkowitz 15:55, 8 July 2009 (UTC)		2

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Scuticaria
Scuticaria steelei
Scientific classification
Domain: Eukaryota Kingdom: Plantae Division: Magnoliophyta Class: Liliopsida Order: Asparagales Family: Orchidaceae Subfamily: Epidendroideae Tribe: Cymbidieae Subtribe: Maxillariinae Genus: Scuticaria Lindl. 1843
Type species
Maxillaria steelei Hook. 1837
Species
S. hadwenii (Lindl.) Planch. 1852 S. irwiniana Pabst 1973 S. itirapinensis Pabst 1973 S. kautskyi Pabst 1972 S. novaesii F.Barros & Cath. 1982 S. peruviana D.E.Benn. & Christenson 2002 S. salesiana Dressler 1968 S. steelei (Hook.) Lindl. 1843 S. strictifolia Hoehne 1947
Synonyms
None

Scuticaria is a genus in the orchid family formed by nine species of showy flowers and long cylindrical leaves. They are epiphytic, occasionally lithophytic or terrestrial, that grow pending and are cespitosus, or reptant and ascending, which exist in three isolated areas of South America, the Amazon Forest in Ecuador and the Serra do Mar and Serra da Mantiqueira mountains in Brazil, both in shady and sunny places.

The genus Scuticaria has been traditionally placed close to Maxillaria but recent research shows they are more closely related to the genus Bifrenaria. Despite their interesting appearance, the are hardly seen in nature and, because they culture is complicated, they are not common in private collections and orchid shows either. No other use for these species is reported besides ornamentation. Because it is a well established genus, formed by few species that are reasonably easy to separate, there were few publications about them during the last decades.

Distribution and habit

Despite there are few species, Scuticaria inhabit varied climates, disperse in a very uneven way though all countries of South America northern to Bolivia, this excluded, and also in areas of Mata Atlântica in Brazilian Southeast. No species is common in nature, being just occasionally or even rarely found.

The species with wider range is Scuticaria steelei which inhabits open clearings at higher elevations of central Amazon, jungles known as matas de terra firme, up to eight hundred meters of altitude. Although this species occupies wide area, it is not found very often. Another species from Amazon, however, in a much more restricted area, just in Guyana, in places where the altitude is lower and the humidity is higher, is Scuticaria hadwenii var. dogsonii.

Endemic in another area of Amazon, separated but not that far from the habitat of Scuticaria steelei, on southeastern Ecuador, close to the place where the Andes starts, in humid and slightly colder forests, on the mountains up to 1,300 meters of altitude, it is found Scuticaria salesiana. Under the same conditions but in wider areas, that encompass the southeast of Ecuador and northeast of Peru, lives S. peruviana. All species from Amazon are always epiphytic.

The remaining species inhabit the area occupied by Brazilian Atlantic Forest. The only species that can be found widespread through several states is Scuticaria hadwenii, in the humid jungles of Serra do Mar from Santa Catarina to Bahia States, generally found living epiphytic at middle height over thick tree stems. Other species occasionally found, although often under living litophytic over rocks and gatherings of fallen leaves in sunny areas of the mountains of São Paulo and Rio de Janeiro, is S. strictifolia.

Scuticaria irwiniana, second and last rupicolous species, exists only on the mountains of Minas Gerais State, found in sunny or shadier places up to two thousand meters of altitude. Two are the species from Espírito Santo State, S. novaesii and S. kautskyi, both endemic of restricted areas in the dry jungles of the countryside. The last Scuticaria species is S. itirapinensis, which has been found only a couple of times in the west-central dry woods of São Paulo State, in an area which has been highly deforested, close to Itirapina. There are no records or reports on this species, both in nature and under culture, during the last twenty five years. It is speculated about the possibility of its extinction.

Description

(CC) Photo: Dalton Holland Baptista
Scuticaria novaesii.
This is an endemic species from Espirito Santo State in Brazil discovered only in 1981.

The species subordinated to genus Scuticaria are characterized by being plants of thick cylindrical roots covered by thick vellamen. Their stem is formed by a ordinarily short rhizome, slightly elongated in some species; and by cylindrical almost inconspicuous pseudobulbs of the same diameter or slightly thicker than the unique leaf born on their apexes, because they generally are covered by small dried scaling steaths. The leaves may be erect or pending up to one meter long. The inflorescences grow from the said steaths and almost always bear just one flower, exceptionally two in one species, and always is much longer than the pseudobulbs, bearing showy yellow, orange, purple or greenish flowers, with petals and sepals plain, stained or striped, usually by light brown but also by diverse combinations and shades of the other mentioned colors. Ordinarily the labellum presents contrasting colors, frequently with white areas.

The flowers are large, wide open, and last during about two weeks. They have sepals of similar sizes and form an almost invisible chin with the column foot. The petals may be similar to the sepals but smaller, or much smaller and with a much narrower base, occasionally showing different patterns or colors. The labellum articulates with the column, is trilobed, with comparatively small lateral lobes and larger terminal, which has variable shapes with diverse patterns and a callus under to column. The later is é semi-cylindrical, slightly arching, erect and thick, without any kind of appendix, ending in an apical anther and elongated in a small foot at the base. The flowers bear to pairs of pollinia of different sizes. The caudicle is narrow and the retinacle is small. The fruits resemble the ones of Maxillaria. There are no observation records of pollinators activities but Scuticaria are supposedly pollinated by Euglossini bees.

Taxonomic notes

Scuticaria steelei
Illustration of original description published by William Jackson Hooker in 1837.

In May of 1837, the English Botanist William Jackson Hooker received a drawing and a dried sample of a plant, sent by an orchid grower from Liverpool, together with a note explaining that the plant arrived from Demerara, in Guyana, in July of the preceding year. Hooker described this species, classifying it under the genus Maxillaria, calling it M. steelei, in homage to its discover. In his description, Hooker affirms that the plant is highly interesting and an excellent addition to the known epiphytic species because it shows cylindrical leaves almost one meter long, different from anything ever found. few months later, John Lindley published again the species Hooker described, however, adding more information. Two years earlier, several plants had been sent from Demerara and Lindey reports that he had previously informally classified this species as Maxillaria flabellifera which, under this name, could be found in several orchid collection in England. Because he had not yet described this species, he accepts the priority of the name chosen by Hooker. Lindley adds, however, that he had some doubts about the classification, of a species so different from any other known so far, under the genus Maxillaria.

In 1843, Lindley published a revision of a group of orchids classified as tribus Maxillaridae, then subordinated to Vandeae, a subfamily of Orchidaceae at the time. In this revision, he indicates that much work is needed till the limits between each genus within this tribus can be established and states his doubts regarding some of the new genera he was proposing, despite being very sure of other ones. Lindley suggested the division of Maxillaridae in twenty five genera, being Scuticaria one of the genera he considered well established. When describing this new genus, Lindley based on morphologic characteristics of Maxillaria steelei Hook., selected as the Type species of Scuticaria with the name Scuticaria steelei. This name comes from Latin scutica, flagellum, in reference to the long cylindrical leaves that the species of this genus show, similar to the leather whips used to punish.

Strangely, because he published the genus Scuticaria many years earlier, in 1851, Lindley described another species now considered part of this genus, classifying it under Bifrenaria. It is speculated that possibly because it was found in Brazil on the same area in the southeast where most of Bifrenaria were common, or because he believed that two species separated by so long distance belonged to the same genus. It was Scuticaria hadwenii. Few months later, Jules Émile Planchon corrected Lindley moving it to the genus where it is subordinated today. In 1851, the only two common Scuticaria species were described and the genus well established, therefore no later confusion about the classification of any species subordinated to this genus ever happened.

Almost one century passed before any important new information were published. In 1881 Heinrich Gustav Reichenbach described Scuticaria dogsonii, originated from Guyana, but in 1892, Berthold Stein, considering that the only difference it shows from Scuticaria hadwenii is the fact it bears two flowers each inflorescence, reduced it to a variety of the later. In 1903, Célestin Alfred Cogniaux, when revising all orchids species from Brazil, cites two other varieties of Scuticaria hadwenii which, because just show color differences, can not be accepted as such today. Finally, in 1947, Frederico Carlos Hoehne described a new species, Scuticaria strictifolia, yet similar to Scuticaria hadwenii, although showing some slight differences on the labellum structure, besides their normally lithophytic habit and erect leaves.

(CC) Photo: Dalton Holland Baptista
Scuticaria irwiniana.
This is one of the two Scuticaria species with erect leaves and the one with the shortest leaves among all species.

If few species were known so far, after 1968 the number of described species triplicated. All species described during the later years are uncommon and inhabit restricted areas, some are very rare or even supposedly exctinct. In 1968 Robert Louis Dressler described Scuticaria salesiana, discovered in Ecuador in an area far apart from the other Scuticaria range. In 1972, Guido Pabst described Scuticaria kautskyi, found in Espírito Santo State, in southeast Brazil and, during the following year, published two species at once, S. itirapinensis and S. irwiniana. In 1982, other species was discovered in Espírito Santo, Scuticaria novaesii. The last described species was S. peruviana, found in Peru in 2002, in the same region of S. salesiana, to which it is related.

Despite Lindley indicated the possibility of Scuticaria being closely related to Bifrenaria when he initially described S. hadwenii under this genus, all later taxonomists always included Scuticaria on the same group Maxillaria were. It was just in 2000 that the first proofs of Scuticaria closer proximity to Bifrenaria started being published. In 2002, a detailed research about the phylogeny of Bifrenaria performed molecular analyses on two Scuticaria species while chosing them as out groups. This study claims that the phylogenethic internal relationships among Scuticaria species so far remain unknown.

It is known that other orchid genera bearing cylindrical leaves devolved this sort of leaves as a defense to climate changes their habitats were going through along the eras. Terete leaves are capable of much more water and nutrients and to face longer drought periods than species bearing thin leaves, on the other hand, almost all epiphytic species presenting the former type of leaves show more or less atrophied pseudobulbs since the leaves carry on its accumulating role. It is a supposition that Scuticaria species should have once inhabited much drier through their evolution. Because most of the species are found in shadier and more humid species now, this may one of the reasons why their culture uses to be complicated, possibly because the delicate balance they reached in nature is broken. For the same reason it is supposed their frequency in nature is only occasion or rare.

Species

(CC) Photo: Dalton Holland Baptista
Scuticaria hadwenii
This is the most variable among "Scuticaria species and widespead through a large area in Southeast of Brazil.

Because of its highly particular morphologic characteristics which allow immediate identification, their restricted species distribution, and their comparatively low variability, since the genus Scuticaria was established by Lindley, only then species were formally described and it has never been great confusion separating each species. Form these ten, nine are generally accepted, the tenth being ordinarily considered a variety, and, under this condition, also accepted. For identification purposes, the species can be split as follow:

Only two species present erect leaves and are the only ones frequently found as lithophytes, Scuticaria irwiniana, easily known recognized because of its flowers without any stains on the internally entirely purple and externally whitish sepals and petals, with white labellum, striped of purple. This species generally can be identified even without flowers because of its reptant, slightly ascendant growth, and longer rhyzome than any other species. Scuticaria strictifolia also has erect leaves but occasionally, when cultivated under insufficient light, their leaves can be narrower and slightly bent making the distracted observer find hard to differentiate it from S. hadwenii. The Brazilian taxonomist Guido Pabst considered this species a variety of the later.

(CC) Photo: Dalton Holland Baptista
Scuticaria strictifolia
It is very close to Scuticaria hadwenii but has erect leaves; different colors and diverse callus structure on the labellum.

All species remaining are ephiphytic with pendent habit. Scuticaria hadwenii, due to its several more or less isolated groups of populations along Serra do Mar, mostly on the west side of this chain of mountains, spreading throughout the interior highland in some states of Brazil, is the Scuticaria species that presents most variable colors. It can be separated from S. strictifolia because shows leaves always pending, flowers of more vivid colors and by the interior of the labellum, which ordinarily is more pubescent. There is a variety denominated dogsonii, native from Guyana, which is more floriferous.

The two other species from Espírito Santo State are highly different to each other. Scuticaria kautskyi usually has more or less uniform orange color on its sepals and petals, with their bases slightly lighter and dotted of greenish yellow. Their labellum is white showing few colored drawings and narrow terminal lobe, slightly deflected. The other species from this state, Scuticaria novaesii presents flowers with green-yellow segments, intensely spotted with dark brown and wide and flat labellum terminal lobe, with clearly marked by radial multicolored lines.

Scuticaria itirapinensis, the last species of brazilian southeast, is the one that closely resembles Amazonian Scuticaria steelei, although it can be easily separeted because of its strong yellow flowers and much shorter leaves, besides slight differences on the proportions of floral structures. A Scuticaria steelei presents entirely pale yellow flowers, completely covered by spaced small darker stains, However in is not even necessary to observe the flowers to identify it as their leaves are about one meter long, and there are references of plants measuring almost one and a half meter.

The last two Scuticariaare isolated in forests of Peru and Ecuador and are similar to each other. They are different from all other because of the proportions of floral segments. The labellum is much larger when compared to their sepals and petals than it is on other species. Moreover, their petals are striped of brown and much smaller than the sepals, showing a greater difference than it is found on the other species. From each other, they can be separated mostly by the shape of the labellum. Scuticaria salesiana presents more rounded intermediate lobe, and Scuticaria peruviana has it more rectangular, with the apex truncated, almost in a straight line.

In 2008, a new species of Scuticaria, S. bahiensis has been described from Bahia state in Brazil but so far it remains mostly unknown.

Culture

Scuticaria itirapinensis.
This showy species has been found just a couple ot times in nature and has not been found or seen anywhere during the last decades.

In his book Flora Brasilica, the Brazilian Botanist Frederico Hoehne strongly recommended the culture of Scuticaria species because of their beautiful flowers and interesting vegetation, however, soon later he admits that all species then cultivated by São Paulo Botanic Garden had died after two or three years. Indeed, he claims that to successfully grow them a special environment needs to be created. These plants are not easy to maintain under culture. Only recently, with the help of modern technology, timers and foggers that keep the humidity constant, the growers have been finally capable of keeping them out of their natural environment for several years.

There are four different sorts of culture according to the origin of each species. S. steelei and S. hadwenii var. dogsonii are the species that need higher temperature and humidity. The two rupicolous species, S. irwiniana and S. strictifolia ate the ones which need more light and constant ventilation besides drier culture conditions. S. peruviana and S. salesiana take slightly cooler temperatures than the other species although still need humidity mostly during the early morning hours. The other species need less light than the mentioned ones. All species should be preferably mounted on plaques of vegetable fibers because of their pending habit, the rupicolous species may alternatively potted in well drained pots. Scuticaria are delicate plants that like to remain untouched during several years because their roots easily resent on replants.

References

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Previous Winners

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•  Bifrenaria: A genus of orchids formed by circa twenty species of South America, some widely cultivated because of their large and colored flowers; divided in two distinct groups, one with large flowers and short inflorescences and the other with small flowers and long inflorescences. ^[e] (June 11)
•  Halobacterium NRC-1: A microorganism from the Archaea kingdom perfectly suited for life in highly saline environments giving biologists an ideal specimen for genetic studies. ^[e] (June 4)
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•  Orchid: Any plant classified under Orchidaceae, one of the largest plant families and the largest among Monocotyledons. ^[e] (Mar 31)
•  Oliver Cromwell: (1599-1658) English soldier, statesman, and leader of the Puritan revolution, nicknamed "Old Ironsides". ^[e] (Mar 24)
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See Also

• CZ:New Draft of the Week
• CZ:Markup tags for partial transclusion of selected text in an article
• CZ:Monthly Write-a-Thon

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