Nomenclature Quick Guide
Usually, for the average conifer gardener, the only plant names they have to deal with a the Genus, Species and Cultivar. However, botanists — and taxonomists in particular — look at these things much more closely and have designations for the slightest differences they find in plants from the same species. These designations can be subjective and there is often disagreement among taxonomists and even the different scientific bodies that determine plant names.
Here is a simple guide to the terms they use and what they mean:
A Cultivar is a cultivated variety, a particular plant that has arisen either naturally or through deliberate hybridization, and can be reproduced (vegetatively or by seed) to produce more of the same plant. The Cultivar name follows the Genus and Species name. It is written in the language of the person who first described it, and should not be translated. It is written in single quotation marks but sometimes it has cv. written in front of the name.
Some cultivars have a Latin name but the latinate between the single quotes is not italicized. All cultivars names given after 1959 have to be in a modern language; those in circulation prior to this date were allowed to keep their Latin names but not italicized.
Cultivars are the lingua franca of conifer collectors. Some ACS members will fall in love with white pines (Pinus strobus) and collect dozens of them from Pinus strobus ‘Alba’ to Pinus strobus ‘Witches Brew.’ (And there is probably somebody out there now looking for a new white pine cultivar to name ‘Zebra.’)
A Hybrid is the result of two plant species interbreeding either in the wild or in the garden with human help. Their names are separated by the multiplication sign (“x”). Most hybrids are between the same species like one of the 2014 CCOY selections, Pinus x schwerinii ‘Wiethorst.’ This is a cross between the Eastern white pine (Pinus strobus) and the Himalayan white pine (Pinus wallichiana). Less common are hybrids of plants from different genera.
A Subspecies (abbreviated subsp. or, rarely, ssp.) occurs in some species that have a wide distribution in the wild across large geographical areas but with very different weather and soil such that they develop slight differences in their populations based on their location. The differences can manifest themselves in slight color change, height or form that can result in them being designated a subspecies.
A Variety (abbreviated var.) is a plant that, like a subspecies, can have the same slight differences. However, it occurs sporadically across the whole range of the species and is not limited to the same geographic boundaries of the subspecies. The term “var.” should always be used prior to the named variety at the end of the plant name.
A Form (abbreviated f.) is a plant that has minor botanical differences, such as the color of the flower or shape of the leaves. The form name (such as lutea to designate yellow) follows the Genus and Species name, with form (or f.) after the individual species name. It is italicized.