Week4-5 Taxonomy-1.pdf

Plant Identification  Identification ›is the process of associating an unknown entity with a known entity (or recognizing that the unknown entity does not have a known counterpart). ›Basic ability ›Ability to recognize diagnostic characterization (= diagnosis) ›If the characteristics...

Plant Identification  Identification ›is the process of associating an unknown entity with a known entity (or recognizing that the unknown entity does not have a known counterpart). ›Basic ability ›Ability to recognize diagnostic characterization (= diagnosis) ›If the characteristics of the unknown entity fall within the range of the diagnosis of a known one, then an identification is made. Methods of Identification ›Taxonomic Keys ›Written Description ›Specimen Comparison ›Floras and Monographs ›Image comparison ›Expert Determination  Taxonomic Key › Key - is an identification device that consists of sequentially choosing among a list of possibilities until the possibilities are narrowed down to one › key may or may not split a larger group into smaller, natural (monophyletic) subgroups ex. Dichotomous key and Polyclave Key Dichotomous key consists of a sequence of two contrasting statements, each statement known as a lead; the two leads together comprise a couplet  Dichotomous Key › A well-written dichotomous key may have several types of evidence presented, with every character of the first lead matched, respectively, in the second lead artificial or practical, meaning that the sequential groupings of the key do not intentionally reflect natural groups natural or phylogenetic, in which diagnostic (or even apomorphic) features are used to delimit natural groups, which are usually formal taxa Tips in reading Keys ›read all parts of both leads ›Never read just the first lead ›after reading both leads of a couplet, if you are not certain which is correct, both should be considered. ›The two (or more) possibilities attained can then be checked against descriptions, illustrations, or specimen comparisons.  Polyclave Key › consists of a list of numerous character states, whereby the user selects all of states that match the specimen › Based on which of the many character states are a match, the correct taxon (or closest match) can be determined or narrowed down to a smaller subset of the possibilities. › All polyclave keys in use today are implemented by a computer algorithm.  Advantages of Polyclave Key › they permit the use of a limited subset of information to at least narrow down the possibilities › often enable the user to identify the plant, even if one or more types of data are missing from the specimen › if the specimen cannot be absolutely identified, its identity may at least be narrowed down to a few alternatives, which can then be checked by other means Disadvantages of Polyclave Key ›Availability (they have generally been written only for a limited number of taxonomic groups)  Written Description › compare features of the unknown plant with written descriptions of the possible known taxa › good method of determining with certainty whether the range of variation of the unknown plant corresponds to that listed in the description of a known plant. › written descriptions are best used to verify an identity › after one or a few possibilities are presented Disadvantages of Description › reading all of the written descriptions of a flora is impractical, this method relies on narrowing down the possibilities first. › gleaning the diagnostic characteristics from a long list of features may be difficult Specimen Comparison › to compare the plant in question to a live or preserved plant collection, usually an identified herbarium specimen › excellent method of identification, as many features of a plant (e.g., coloration and surface features) are often not adequately denoted in written descriptions or visible from photographs or illustrations › Synoptic collections, which house generally one specimen of each taxon for a given region (e.g., a county), are very useful in this regard. Specimen Comparison ›Precaution - it is dependent on the fact that the herbarium specimens are themselves correctly identified. Thus, a possible match should always be verified with a written description Image Comparison › comparing it to photographs or illustrations of known taxa › These are usually obtained from books, although Webpage images have now become a very useful resource › visual comparison to an image can still be an excellent way to identify a plant, particularly if the possibilities can be narrowed down beforehand Image Comparison ›Precaution - this method is that two or more taxa may look very similar to one another as based on a photograph or illustration; the differences between them may reside on obscure morphological features that are not easily visible Expert Determination › This method may be time-consuming, as it usually requires ending a specimen away for identification (as well as knowing who the experts of a given group are). › Expert identification is perhaps the best way to identify a specimen, as the expert will usually know the taxa of that group over a wide geographic range. › Expert determination is often essential for certain groups in which species or infraspecific identification is very difficult.  Tips J › The importance of correctly identifying a specimen cannot be overstated. › Once a determination is made, it should be viewed as only tentative. Never assume you have reached the correct answer in using an y one method › it is important to check your determination by all available means. Be your own devil s advocate; check and recheck yourself. › Verify every identification against a written description and comparison to an herbarium specimen. › Some groups may be particularly difficult to identify, being composed of a great number of taxa that differ from one another by obscure features. › Proceed very carefully, and don t hesitate to send off specimens for expert determination if needed.  Tips J › one should always be conscious of the possibility that the identification process points to a new taxon. › If a thorough evaluation of available references indicates that the unknown plant in question does not match any known taxa listed in a flora, then the plant may be a new record (either native or naturalized) for the geographic range of that flora. › In some cases, the unidentifiable taxon may be new to science, warranting the valid publication of a new taxon. Plant Nomenclature Nomenclature › is the assignment of names utilizing a formal system › Botanical names serve as symbols of a group of natural entities for the purpose of communication and data reference. International Code of Botanical Nomenclature (ICBN or ICN) International Code of Botanical Nomenclature (ICBN) › include not only the land plants, but also the blue-green algae (Cyanobacteria); fungi, including chytrids, oomycetes, and slime molds; photosynthetic protists and taxonomically related non-photosynthetic groups › (1) naming new taxa, which were previously unnamed and often not described; and › (2) determining the correct name for previously named taxa, which may have been divided, united, transferred, or changedin rank › Legitimate names are those that are in accordance with the rules of the International Code of Botanical Nomenclature. › Any name that violates one or more rules of the ICBN is known as an illegitimate name. › A valid name is one that is validly published (see later discussion). The rules of the ICBN can be somewhat complex, often necessitating careful scrutiny (and a lawyerlike mentality). Principles of Nomenclature › I. Botanical nomenclature is independent of zoological and bacteriological nomenclature. The Code applies equally to names of taxonomic groups treated as plants whether or not these groups were originally so treated. › II. The application of names of taxonomic groups is determined by means of nomenclatural types. › III. The nomenclature of a taxonomic group is based upon priority of publication. ›IV. Each taxonomic group with a particular circumscription, position, and rank can bear only one correct name, the earliest that is in accordance with the Rules, except in specified cases. ›V. Scientific names of taxonomic groups are treated as Latin regardless of their derivation. ›VI. The Rules of nomenclature are retroactive unless expressly limited. Terminologies ›Rules (which are mandatory and written out as Articles) ›Notes (which are binding and clarifying), ›Recommendations (which are not binding but suggested), ›And explanatory Examples and Footnotes.  Scientific Names ›The names assigned by the rules of the ICBN Pisum sativum are known as scientific names. Scientific names are, by convention, in the Latin language ›Binomial ›Genus + Specific epithet ›Th especific epithet may be capitalized if it is a commemorative (named after a person or place), but this is optional; the trend today is to never capitalize the specific epithet. Binomial species names are always either italicized or underlined. Vernacular names (Common names) ›Common names are not formally published and are governed by no rules. ×Only specific names are universal ×Not consistent ×Tell nothing about ranks ×Not all organisms have common names Ipomea – morning glory - woodbine  Ranks ›Classified hierarchy of any taxa in which higher taxa is inclusive of all lower ranks ›Each scientific name of a particular rank must end in a certain suffix according to the rules and recommendations of the ICBN ›The trend today is to consistently apply the type principle by using the standardized family names that end in - aceae and to use subfamily names that are based on these (e.g., to use F aboideae o ver P apilionoideae ). exemptions acceptance of eight alternative family names, none of which end in -aceae. › Compositae (= Asteraceae), › Cruciferae (= Brassicaceae), › Gramineae (= Poaceae), › Guttiferae (= Clusiaceae/Hypericaceae), › Labiatae (= Lamiaceae), › Leguminosae (= Fabaceae), › Palmae (= Arecaceae), › Umbelliferae (= Apiaceae). Position ›is the placement of a taxon as a member of another taxon of the next higher rank. the position of the genus Aster is as a member of the family Asteraceae. Taxa may be the same in rank but differ in position. Rosa and Aster are both at the rank of genus but differ in position, the former in the Rosaceae, the latter in the Asteraceae.  Trinomials ›Subspecific epithet and varietal epithet Toxicodendron radicans ssp. diversilobum Brickellia arguta var. odontolepis Authorship › All scientific names at and below the rank of family have an author, the name of the person who first validly published the name › Author names are often abbreviated, such as › Haemodoraceae R. Br. (for Robert Brown) or › Liquidambar styraciflua L. ( L. being the standardized abbreviation for Linnaeus).  Nomenclatural Types scientific names must be associated with some physical entity, › Holotype - is the one specimen or illustration upon which a name is based, originally used or designated at the time of publication. › Isotype - is a duplicate specimen of the holotype, collected at the same time by the same person from the same population › Lectotypes - is a specimen that is selected from the original material to serve as the type when no holotype was designated it the time of publication, if the holotype is missing, or if the original type consisted of more than one specimen or taxon. › Neotype - is a specimen derived from a nonoriginal collection that is selected to serve as the type as long as all of the material on which the name was originally based is missing › Syntype - which is any specimen that was cited in the original work when a holotype was not designated › Paratype - a specimen cited but that is not a holotype, isotype, or syntype › Epitype - a specimen (or illustration) that is selected to serve as the type if the holotype, lectotype, or neotype is ambiguous with respect to the identification and diagnosis of the taxon  Conservation of Names ›One adverse effect of the principle of priority is that scientific names that are well known and frequently used may be replaced by some other name if the latter was discovered to have been published earlier. ›petition may be presented (in the botanical journal Taxon) and voted upon at the International Botanical Congress to conserve one name over another that actually has priority. Name Changes ›Name changes can occur for only two reasons: (1)because of the recognition that one name is contrary to the rules (i.e., is illegitimate), and thus, another name must take its place; or (2)because additional taxonomic study or research (for example, a cladistic analysis) has resulted in a change of the definition and delimitation of a taxon; this process is known as a taxonomic revision. ›Divided - larger taxon is divided into two or more smaller taxa of the same rank, the terms sensu lato (abbreviated s.l.) and sensu stricto (abbreviated s.str. or s.s.) The genus Carduus of the family Asteraceae is often split into two genera: Carduus, having barbellate pappus bristles, and Cirsium, having plumose pappus bristles ›United - One reason for uniting taxa is the recognition that features previously used to distinguish them are, upon more detailed study, unsupportive of their being different The species Bebbia juncea and Bebbia aspera, which were considered indistinct and were united into one species, B. juncea ›Transferred in position – from one taxon to another of the same rank The species Rhus laurina was transferred in position as a member of the genus Malosma, the new species name being Malosma laurina ›Changed in Rank - Note in the two rank change examples just given that the original names for the epithets are retained. The retention of a name that is changed in rank is recommended (but not required) by the ICBN, but only if an earlier name for the same taxon had not already been published at that rank (and also, only if the same name had not already been used for another taxon; see homonym). The species Eruca sativa was changed to the rank of subspecies (of the species E. vesicaria), the new combination being Eruca vesicaria ssp. sativa › Basionym - is the name-bringing or epithet-bringing synonym, i.e., the original (but now rejected) name, part of which has been used in a new combination. › The name of the author(s) who originally named the basionym is also retained and placed in parentheses ahead of the author who made the change. When Dilatris caroliniana Lam. was transferred to the genus Lachnanthes by Dandy, the new species name became Lachnanthes caroliniana (Lam.) Dandy. The basionym in this case is Dilatris caroliniana Lam. ›Autonym - is an automatically created name for infrafamilial, infrageneric, and infraspecific taxa. Autonyms are used whenever a family is divided into subfamilies, tribes, or subtribes; a genus is divided into subgenera or sections; or a species is divided into subspecies or varieties. Isely split Lotus stipularis (Benth.) E. Greene into two varieties: L. stipularis (Benth.) E. Greene var. ottleyi Isely and L. stipularis (Benth.) E. Greene var. stipularis; note that the latter variety, containing the autonym, lacks authorship because its type is the same as that for the originally described species Synonyms › is a rejected name, by a particular author or authors. Synonyms are rejected for either of two reasons: (1) because they are illegitimate, i.e., contrary to the rules of the ICBN; or (2) because of taxonomic judgment, i.e., Synonyms may be based on the same or on a different type specimen from the correct name › Malosma laurina (Nutt.) Abrams [Rhus laurina Nutt.] Homonym › is one of two (or more) identical names (not including authorship) that are based on different type specimens. The later homonym, based on publication date, is illegitimate Tapeinanthus Herb. (1837), of the Amaryllidaceae, and Tapeinanthus Boiss. ex Benth. (1848), of the Lamiaceae, are homonyms. The later homonym in the Lamiaceae is illegitimate [and was renamed Thuspeinanta T. Durand (1888)].  Tautonym › is a binomial in which the genus name and specific epithet are identical in spelling › Tautonyms are not permitted in botanical nomenclature the name Helianthus helianthus is a tautonym and illegitimate, whereas Helianthus helianthoides is not a tautonym and would be permitted. (Note that zoological nomenclature does permit tautonyms, as in Gorilla gorilla.) Valid Publication in order for a scientific name to be formally recognized, it must be validly published › The name must be effectively published, which means that it must be published in a journal commonly available to botanists › the name must be published in the correct form, i.e., properly Latinized with the rank indicated › the name must be published with a Latin description or diagnosis or with a reference to such › for taxa of the rank of genus and below, a nomenclatural type must be indicated Correct Name ›is a legitimate (and therefore validly published) name that is accepted by a particular author or authors Abbreviations › sp. nov. following a binomial (e.g., Eryngium pendletonensis, sp. nov. ) refers to the Latin species nova and means that the species is new to science › gen. nov. (genus novum) cites a new genus name. › comb. nov. following a binomial refers to the Latin combinatio nova and means that the taxon has recently been transferred to a new position or rank. Porella acutifolia (Lehm. & Lindenb.) Trevis. var. ligulifolia (Steph.) M. L. So, comb. nov. › aff. preceding a taxon name literally means related to (Latin affinis, related, connected ), as in Calyptridium aff. monandrum or af f. Calyptridium monandrum. › cf. (Latin confer, compare ) preceding a taxon name, as in Calyptridium cf. monandrum or cf. Calyptridium monandrum › s.l. (sensu lato) means in the broad sense, referring to a broad, inclusi ve taxon circumscription, › s.str. or s.s. (sensu stricto) means in the strict sense, referring to a narrow, exclusive taxon circumscription. 1. auct. non (auctorum non) refers to a misapplication of a name, such that the type specimen of the name does not fall within the circumscription of the taxon being referred to by that name 2. emend. (emendatio) means a correction or amendment 3. et is Latin for and 4. nom. cons. (nomen conservandum) means a conserved name 5. nom. nov. (nomen novum) means a new name 6. nom. nud. (nomen nudum) means published without a description or diagnosis, making the name invalid 7. non is Latin for not 8. orth. cons. (orthographia conservanda) means a conserved spelling 9 stat. nov. (status novus) means a change in rank, e.g., elevating a varietal name to specific status 10. typ. cons. (typus conservandus) means a conserved type specimen 11. typ. des. (typus designatus) means the designation of a type specimen 12. vide (video) means to cite a reference 13. ! (symbol for vidi, I ha ve seen it ) means a conf irmation of a name Botanical Names Amaranthus is masculine Crassula is feminine Polygonum is neutral Exemptions ›tree genera are typically treated as feminine, regardless of the ending ›feminine in gender, even though they have masculine endings Quercus, Pinus, and Liquidambar Name change ›Haplopappus squarrosus, the ending (-us) is masculine. ›When this species is transferred to the genus Hazardia, the new name becomes Hazardia squarrosa Number ›Names of genera ›infrageneric names ›(such as subgenera or sections), and species or infraspecific combinations are all treated as the singular case in Latin ›all taxon names above the rank of genus are treated as Latin plural nouns ›Orchidaceae are a large family of monocotyledons and ›The Rosales consist of many species. Commemoratives ›Commemorative names are those named after a person or place. ›Specific or infraspecific commemorative names are usually treated as the genitive case (denoting possession) and must have genitive endings 1. Male – ii Isoetes orcuttii (unless the terminal consonant is -r or -y, in which case a single -i is used, as in Erigeron breweri) 2. -i, if the name ends in a vowel other than a, as in Arctostaphylos pringlei 3. Female commemorative names (regardless of ending) an -e is added, as in Baccharis vanessae or Carex barbarae. ›commemorative name is treated as an adjective, in which case the endings - ianus, -iana, or –ianum may be used. Lotus nuttallianus (named after Thomas Nuttall) Prunus caroliniana (named after the Carolinas) Antirrhinum coulterianum (named after John M. Coulter). Pronunciation of Names (Diphthongs)