Plumeria Classification

In the overall scheme of things, Plumeria are classified as follows:

Kingdom: Plantae - Plants
Subkingdom: Tracheobionta - Vascular plants
Superdivision: Spermatophyta - Seed plants
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida - Dicotyledons
Subclass: Asteridae
Order: Gentianales
Family: Apocynaceae - Dogbane family. The Apocynaceae are trees, shrubs or sometimes herbs, usually with milky sap comprising about 200 genera and 2,000 species. The leaves are simple, usually opposite and decussate, or whorled; stipules are usually absent. The flowers are bisexual and actinomorphic or sometimes weakly zygomorphic. The calyx is synsepalous and usually 5-lobed. The corolla is sympetalous and usually 5-lobed. The stamens are distinct, as many as corolla lobes and alternate with them, and adnate to the corolla tube (or perigynous zone). The anthers are introrse and commonly adherent to the surface of the stigma. The gynoecium consists of a single compound pistil of 2 carpels that may be distinct at the level of the superior or rarely partly inferior ovary but which are united by a single style. When distinct, each ovary typically has few to numerous ovules on marginal placentae; when connate, the placentation is axile or intruded parietal. A nectary consisting of 5 glands or an annular ring is usually found at the base of the ovary. The fruit is commonly a follicle, capsule, or berry. The seeds usually are flat and winged or have a tuft of hairs at one end.
Genus: Plumeria L. - plumeria
Species: example: Plumeria Obtusa L.
Cultivar: example: 'Singapore White'

Using Plumeria Obtusa L. 'Singapore White' as an example, the typical horticultural species name that is given to a plant has three parts: the two-name binomial with author designation, plus a cultivar name.
Plumeria
genus The genus name designates a group of closely related plants which have enough in common to be distinguished from other such groups. A genus may include one or more species.
Obtusa
specific epithet The specific epithet is often a descriptive word: alba (white), brevis (short), sativa (cultivated), etc
. Plumeria Obtusa (Genus + specific epithet)
species The genus and specific epithet compose the species name which is underlined or italicized. By definition a species is a distinct succession of interbreeding individuals from gneration to generation. When two different species cross, the result is an interspecific hybrid designated: Less common is the intergeneric cross.
L.
The author designation is either a single letter or an abbreviation which indicates the originator of the name. It is often omitted in horticultural trade literature such as catalogs. For Plumeria L stands for Linnaeus. Plumeria was named formally by Linnaeus in 1753 for Charles Plumier (1646-1704), a French missionary who lived and collected plants in the West Indies in 1689, 1693 and in 1695. Plumier prepared a detailed manuscript of his botanical discoveries and made some 6000 original field sketches and drawings. These are now housed at the Muséum d'Histoire naturelle in Paris. Linnaeus examined a set of copies made by Claude Aubriet which are now in the University Library at Groningen. These copies were also used by Johannes Burman who prepared and published 262 plates in Plantarum americanarum from 1755 until 1760. Plumier himself published three important pre-1753 works which were used by Linnaeus to understand tropical American plants: Description des plantes de l'Amérique (1693), Nova plantarum americanarum genera (1703), and Traité des fougères de l'Amerique (1705). The latter was particularly important in Linnaeus's treatment of American ferns. The seventeen species of the genus Plumeria were originally found only in tropical America. In the wild these are pachycaulous trees and shrubs. Plumeria rubra is widely cultivated as a flowering shrub especially in the warmer regions of the world. The genus belongs to the dogbane family, Apocynaceae Adans. The genus is the type of a large and complex tropical subfamily frequently termed Plumerioideae Leurss. (1882), although the correct name for the assembly is subf. Rauvolfioideae Kostel. (1834). The taxon is sometimes separated as its own family, Plumeriaceae Horan. 'Singapore White' cultivar. The term cultivar was coined by Liberty Hyde Bailey in the first part of the century from 'cultivated variety.' This term is defined as 'an assemblage of cultivated plants which is clearly distinguishable by any characters (morphological, physiological, cytological, chemical, or other) and which, when reproduced sexually or asexually retains its distinguishing characters.' A cultivar may be propagated sexually or asexually. For Plumeria, Cultivars are usually produced from seed and therefore exhibit some variation in traits other than that for which the selection was made.