In the last column I delved into the mystery of plant names, specifically genus and species.  If you’ve figured those out, well done!
Let’s move onto a little more detailed aspect this week and look at subspecies, varieties, cultivars and hybrids.  Remember, it may seem very complex initially, but once you become familiar with a few plants and their names it all starts to make a bit of sense.  Start in your own backyard and soon the Latin names will be tripping musically off your tongue.
This distinction between subspecies and variety is something that only taxonomists (people who name plants) need worry about.  They are used to describe differences between two plants of the same species.
A very good example is Acer palmatum atropurpureum.  Acer palmatum is commonly known as Japanese maple, and is similar in every way to Acer palmatum atropurpureum, except that the latter has reddish-purple leaves while the former has green leaves.  Another example is Acer palmatum dissectum, with the dissectum referring to the very finely cut leaves of this graceful plant.
Subspecies and varieties are only rarely seen in garden centres.  Of much more interst and use to the average gardener are cultivar and hybrid names.  Cultivars are selelcted forms of species that have a particular trait.  They are usually in “plain” language, not Latin, and often tell a lot about the plant, although many times they won’t tell you anything.
Potentilla fruticosa “Pink Beauty” has, of course, pink flowers, while “Red Ace” has reddish-orange blooms.  But “Abbotswood” has white flowers.  Who knew?
As with species names there are many sources of inspiration for cultivars names.  Prunus cerasifera “Pissardi” is named after Mr. Pissard, the French gardener to the Shah of Iran.  Juniperus horizontalis “Wiltoni” the very popular ground-hugging juniper was introduced by Wilton Nurseries of Connecticut.  Cultivar names are becoming more modernized, as evidenced by Penstemon fruticosus “Purple Haze.”  Jimi Hendrix would be pleased.
Hybrids take good qualities from two different species and create a new plant.  They are identified in plant literature by an x between the genus and the new name.  A familiar hybrid is a cross between Prunus pumila and the aforementioned “Pissardi” plum.  We know it as Prunus x cistena, or the Purpleleaf Sandcherry.  Most of the popular forms of spirea such as “Anthony Waterer” and “Goldflame” are a result of a cross between Spirea albiflora and Spirea japonica, resulting in Spirea x bumalda.
 To make things even more interesting taxonomists are continually updating (and thus changing) genus, species, variety, cultivar and hybrid names.  For instance, a few years ago the large Chrysanthemum genus was split up.  The group of perennials known as Shasta daisies was renamed Leucanthemum to distinguish them from the florist and garden mums.