Plant Taxonomy

Carolus Linnaeus

• sweedish botanist

• came up with binomial name

The system of naming

Binomial System of Nomenclature

Binomial nomenclature

A system for giving each organism a two-word scientific name

• Zea mays: species

• Both names must be:

  underlined (separately) (when writing in ink) or

  italicized (when typing/soft copy)

• Genus name can be used alone to designate all species in the genus

• Specific epithet, designate the species, usually a word that describe some particular quality of the organism, never used alone, always preceded by the full or abbreviated generic name

• Specific epithet can be used in more than one genus

• Citation of Author’s Name

• A complete botanical/scientific name for a particular plant, it must be followed by the name of the person who have identified and described the plant

  • E.g Sesamum indicum named by Linnaeus → Sesamum indicum L.

Genus

• Genus name represents a group of plants with similar characteristics

• In evolutionary terms the genus name represents a common ancestor for all the plants contained in the genus

Species

• The species is the basic unit of classification

• It represent a sub-group of one or more plants within the genus; with similar characteristic

Subspecies (subsp.)

• Geographically distinct population within a species that evolve by natural selection

• Display certain characteristics that distinguish them from other population of the same species

• If they can interbreed, they are not truly separate species but are known as subspecies

Variety

• Within a species there can be minor characteristics that differ from the usual characteristics of the species

• The variations can occur either naturally through cross fertilization of plants or deliberate breeding of plants

• These characters do not have a clearly defined geographical or ecological distribution.

• A naturally occurring variety is referred to as variety.

• A bred variety is referred to as cultivar (cultivated variety)

• E.g. Eucalyptus ovata var. grandiflora

Cultivars

• Plants that are produced using techniques such as selective breeding, in an effort to produce a better or more attractive varieties.

• Cultivar is an abbreviated form of cultivated variety

• The cultivar name will be chosen by the breeder and will therefore be in the native language

• Bougainvillea glabra ‘Singapore Pink’

• Papaver orientalis ‘Mrs Perry’

Hybrid

• Hybrids results from the sexual reproduction or interbreeding between different varieties, species or genera (singular genus).

• It mostly of related species, almost always in the same genus.

• E.g. Eucalyptus camaldulensis x E. ovata

• Hybrid between two different species has an ‘x’ placed in front of the species name

• Magnolia x soulangiana

• Hybrid between two different genera has an ‘x’ placed in front of the genus name, e.g x Osmaria burkwoodii

Leaf type?

Leaf type?

Leaf arrangement?

Leaf arrangement?

Leaf arrangement?

Leaf arrangement?

Flower parts?