Leaf-petiole climbers that hold the stem in 

 place by twining around an adjacent branch 



Clematis spp. and hybrids. 



Plant Nomenclature 



The guiding principles for the regulation of plant 

 nomenclature are embodied in two contemporary 

 documents: (1) the International Code of Botani- 

 cal Nomenclature, 1988 edition (called the Botani- 

 cal Code) and (2) the International Code of No- 

 menclature for Cultivated Plants, 1980 edition 

 (called the Cultivated Code). The Botanical Code 

 "governs the use of botanical names in Latin 

 form for both cultivated and wild plants, except 

 for graft chimaeras" (Brickell et al. 1980: 11). 

 The Cultivated Code regulates nomenclatural 

 matters related exclusively to agricultural, horti- 

 cultural, and silvicultural cultivars. 



Reasons for changing plant names are rooted in 

 the rule of priority stated in Article 1 1 of the 

 Botanical Code. For a genus, the correct epithet 

 is the earliest legitimate one at the same rank, 

 except for a conserved name (nomen conservan- 

 dum); for example, Pseudolarix Gordon (1858) not 

 Chrysolarix H.E. Moore (1965). In categories 

 below the rank of genus, the correct name is the 

 earliest legitimate name at the same rank — 

 species, subspecies, varietas, or forma — to which 

 the plant is assigned. A plant has only one 

 correct name, generally a binary name or bino- 

 mial, that consists of a genus name (for example. 

 Magnolia) followed by a specific epithet (for 

 example, grandiflora) . To this binary name is 

 appended the name of the authority(ies) who 

 published the name. The correct citation of the 

 southern magnolia is Magnolia grandiflora L. ("L." 

 stands for Carl Linnaeus, who first described this 

 species in 1759). Other names for this plant are 

 treated as synonyms (Magnolia foetida Sarg., for 

 example) or homonyms but are illegitimate for 

 purposes of scientific nomenclature. The binary 

 name must be in Latin form regardless of its 

 derivation. Plant nomenclature contains many 

 names adapted from other languages, especially 

 from Greek. 



Names of plants are based on nomenclatural 

 types, usually type specimens, which are docu- 

 mented, dried, and pressed specimens deposited 

 in an herbarium for permanent reference. In the 

 absence of a specimen, an accurate illustration 

 may be substituted for purposes of typification. 

 Botanical names published since 1935 must be 

 accompanied by a Latin diagnosis to be botani- 

 cally legitimate. 



Hierarchy of Rank Categories 

 Genus 



Genus (plural, genera) is the first major taxo- 

 nomic category under the family. The catalog is 

 arranged alphabetically by genus, beginning with 

 Abelia R.Br., assigned to the family 

 Caprifoliaceae and its common name, honey- 

 suckle family. Genera of Caprifoliaceae in the 

 catalog include: Abelia, Diervilla, Dipelta, 

 Heptacodium, Kolkwitzia, Lonicera, Sambucus, 

 Symphoricarpos, Viburnum, and Weigela. Some 

 families are monotypic, comprising a single 

 genus, such as Ginkgo in the Ginkgoaceae and 

 Cercidiphyllum in the Cercidiphyllaceae. For the 

 convenience of the user, the species, subspecies, 

 varietas, forma, and cultivar names are listed 

 alphabetically under each genus without regard 

 to botanical rank. A supplementary list (Appen- 

 dix D) groups the names according to botanical 

 rank. 



Species 



Biologically, the species is the basic taxonomic 

 unit employed in the recognition and classifica- 

 tion of plants. For purposes of this catalog, 

 Cronquist's general definition of species is useful: 

 "Species are the smallest groups that are consis- 

 tently and persistently distinct, and distinguish- 

 able by ordinary means" (1988, p.71). Criteria 

 for the recognition of species may include factors 

 of reproductive isolation, chromosome number, 

 phenetic or morphological discontinuity, geo- 

 graphic isolation, and ecogeographic coherence. 



As the basic unit of biology, the species is subor- 

 dinate to the genus. As the next higher major 

 category, the genus consists of one or more 

 species. The number of species varies from 

 genus to genus. The monotypic genus Ginkgo, 

 for example, consists of a single species, biloba, 

 but the genus Quercus consists of many species, 

 perhaps 450 worldwide, and some genera are 

 even larger. While botanists argue the relative 

 importance of species criteria, the viability of the 

 species as a fundamental biological unit is 

 attested by the presence of over 1,000 Linnean 

 names in the catalog more than 200 years after 

 the death of Linnaeus. 



The word species is either singular or plural 

 (specie refers to coinage). It is abbreviated sp. 

 when singular and spp. when plural. In this 

 catalog, species and cultivar names are cited in 

 strict alphabetical order under the name of the 



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