Plant Nomenclature

Bio 218 Fall 2012

Dr. Dale Benham

Three parts to a binomialErythronium albidum Nutt.1. Genus (plural = genera)

• Latin (or Latinized) = underline or italicize• noun - gendered: masculine, feminine, neuter

2. specific epithet (= species according to some)• Latin (or Latinized) = underline or italicize• adjective or a possessive noun

3. Authority• scientist naming the species (abbreviated name)• rarely used, except for the initial time in an article• Original author(s) ALWAYS remain with name

• becomes parenthetical author(s) when new combination occurs• combining author(s) of NEW combination at end - all others

removed

International Code of Botanical Nomenclature (ICBN)

Two basic activities• naming new taxa• determining the correct name for

previously named taxa

International Code of Botanical Nomenclature (ICBN)

• precise and simple system dealing with:• terms which denote the ranks of

taxonomic groups or units• [subspecies, family, genus, species, variety,

etc.]• the scientific names which are applied

to the individual taxonomic groups of plants

Principles of Nomenclature p. 6121. independent of zoological nomenclature2. application of names of taxonomic groups is determined by

means of nomenclatural types• the specimen which the author cites in the original

description - purely a nomenclatural device, not a biological model

holotype - the single specimen designated by the author from the original collection of the new entity

isotype - duplicates of the holotypelectotype - chosen by someone other than the author, but based

on the author's collectionneotype - chosen in absence of any material from the authorsyntype - any one of 2 or more specimens cited by the author

when no holotype was designated, or any one of two or more specimens simultaneously designated as types

topotype - specimen of a named taxon collected from the original type locality

Type specimen

• designated as specimen on which the species description is based

• dried plant specimen stored in herbarium or museum

• serves as basis for comparison

Principles of Nomenclature3. Nomenclature of a taxonomic group is based upon priority

- the earliest that is in accordance with the Rules is that correct name

4. only one correct name exists for each taxon• valid publication is needed, including the following:

begins 1 May 1753, with the publication of Species Plantarum by Linnaeus

• effective publication (published in printed matter generally available to botanists)• As of 1 Jan 2012:

Electronic material published online in Portable Document Format (PDF) with an International Standard Serial Number (ISSN) or an International Standard Book Number (ISBN) will constitute effective publication

• publication in the form specified for the name of each category of taxa

Principles of Nomenclature• publication with a description or diagnosis (or a

reference to a previously published description or diagnosis)

• accompaniment by a Latin description or diagnosis or by a reference to a previously and effectively published Latin description or diagnosis of the taxon• As of 1 Jan 2012:

A description or diagnosis may be in either Latin or English5. Scientific names of taxonomic groups are treated as Latin

regardless of their derivation6. The Rules of Nomenclature are retroactive unless expressly

limited

Some rules about binomials

• Binomial = scientific name = species (plural & singular)genus + specific epithet

• First letter of genus is the only letter capitalized = Quercus rubra

• No article is used before the name, since it is a proper name ≠ the Abies concolor

• Genus is sometimes abbreviated with first letter followed by a period = Acer saccharinum becomes A. saccharinum

• No tautonomy (repetition of generic and specific epithet names) • Rosa rosa is an illegitimate name

Infraspecific Taxa

• Taxon (taxa = plural)• a group of organisms of any rank given formal recognition

in a classification hierarchy (e.g., class, order, family, genus, species, variety)

• Geographical variation in a species is sometimes noted • subspecies (ssp. or subsp.)• varieties (var.)

• Sporatic, non-geographical variation• normally not named, but some designate as forms (f.)

Do Names Change?

1. Change of taxonomic position:E.g., Sedum variegata transferred to the genusDudleya, the new species Dudleya variegata

2. Change in taxonomic rank:E.g., Larrea divaricata ssp. tridentatachanged to species rank: Larrea tridentata

Basionym

1. The “name bearing” name• Basionym remains in new name, along with original

author2. Keeping track of name changes

E.g., Sedum variegata S. Watson was transferred to the genus Dudleya by Moran, new species name is:• Dudleya variegata (S. Watson) Moran• [Note: Sedum variegata S. Watson is the basionym]E.g., Muhlenbergia shepherdii (Vasey) Swallen transferred to Blepharoneuron by P. M. Peterson & Annable, new name:• Blepharoneuron shepherdii (Vasey) P. M. Peterson & Annable

Autonyms:Automatically created name for infrafamilial, infrageneric, and infraspecific taxaE.g., Lotus stipularis (Benth.) Greene split by Isely into 2 varieties:

Lotus stipularis (Benth.) Greene var. ottleyi Isely Lotus stipularis (Benth.) Greene var. stipularis

Later, genus Hosackia accepted: Hosackia stipularis Benth. var. ottleyi (Isely)

Brouillet Hosackia stipularis Benth. var. stipularis

Fig. 16.2p. 616

What is a synonym?

• a rejected name, by a particular author or authors• Synonyms usually indicated in brackets; e.g., • Malosma laurina (Nutt.) Abrams [Rhus laurina Nutt.]

• illegitimate• taxonomic judgement

Why rejected?

What is a correct name?

• A legitimate (and therefore validly published) name that is accepted by a particular author or authors.

• Each taxon can have only one correct name. How can a name be legitimate but not

correct?• There may be 2 (or more) alternative, legitimate

names.• Only one of these can be correct (in any given

work).

Tracing Nomenclatural History

Notholaena cochisensis GooddingCheilanthes cochisensis (Goodding) MickelCheilanthes sinuata (Lagasca ex Swartz) Domin var. cochisensis (Goodding) MunzNotholaena sinuata (Lagasca ex Swartz) Kaulfuss var. cochisensis (Goodding)

WeatherbyAstrolepis cochisensis (Goodding) D. M. Benham & Windham

Malacothrix incana (Nutt.) Torrey & A. Gray[Malacomeris incanus Nutt.] (=basionym)

Porophyllum gracile Benth.[P. caesium Greene; P. vaseyi Greene]

Gilia diegensis (Munz) A. D. & V. E. Grant[Gilia inconspicua (Sm.) Sweet var. diegensis Munz] (=basionym)

Other examples of synonyms

Abbreviations:"in" = "in the publication of" E.g., Arabis sparsiflora Nutt. in T. & G.May be abbrev: Arabis sparsiflora Nutt.

"ex" = "validly published by."E.g., Microseris elegans Greene ex A. GrayMay be abbrev.: Microseris elegans A. Gray.

Abbreviations"x" = a hybrid.E.g., Salvia xpalmeri (A. Gray) Greene= S. apiana x S. clevelandii.

"sp. nov." = species novum E.g., "Eryngium pendletonense sp. nov."

"cf." = confer, meaning "compare."E.g., "Calyptridium cf. monandrum"