1. Share more characteristics than they do with species in other genera

  2. Individual plants within species share more characteristics than with individual plants in another species

  3. Some genera contain many species, some contain just one

UNKNOWN SPECIES within genus

  1. sp. as shorthand

  2. Plural is spp.

  3. e.g. Lathyrus spp. may mean sweet pea (Lathyrus odoratus), spring pea (Lathyrus vernus), beach pea (Lathyrus japonica) or any other of spp. (of 160)


subspecies (subsp. or ssp) - distinctive geographical ‘races’

varietas or variety (var.) - finer delimited groups (not necessarily geographical)

forma or form (f.) - minor but constant characters separate subgroup (e.g. flower colour)

cultivar (cv) - cultivated variety; some horticultural or agricultural significance (typically from human selection and artificial propagation) e.g. Lathyrus latifolius ‘Rose Queen’

Missing specific epithet

e.g. Fuchsia ‘Mrs Popple’; Lathyrus latifolius ‘White Pearl’


Generic name: Taxus

Specific epithet: baccata

Species (binomial name) : Taxus baccata

A cultivar in species: ‘Adpressa Variegata'

Used for colour (variegated evergreen) and architectural feature


  1. Interspecific hybrids between closely related species within same genus

  2. Origin of most horticultural cultivars

  3. Also found in nature

  4. e.g. Interspecific Hybrid Camelia japonica and C. saluenensis = Camilia x williamsii

  5. Bigeneric hybrids result of hybridising two genera within same family

  6. Less common than IH

  7. e.g. Cupressus and Xanthocyparis = Cupressocyparis (x Cuprocyparis leylandii)

  8. Graft: a genetic hybrid (chimaera) denoted by +

  9. Very rare

  10. e.g. Chamaecytisus pupureus (purple broom) and Laburnum anagyroides = +Laburnocytisus ‘Adamii’

trade designations

e.g. Rosa Ingrid Bergman = ‘Poulman’

Genus: Rosa

Specific epithet: None (origin of parent untraceable)

Trade Designation: Ingrid Bergman (changed country to country, or for marketing)

Cultivar: ‘Poulman’ (scientific cultivar name cannot be changed)