Finally, in the nomenclature system, we have to account for 

variation within species and other special categories

•

As mentioned previously, variable species are often given 
subspecific or varietal names. In this case, the varietal name is 
also italicized and starts with a lower case letter, but always 
follows the specific epithet

•

An example of how this works is with the Garry oak, 

Quercus 

garryana

, a tree common in Northern California

•

However, there is a shrub version of the same oak, and so it’s 
distinguished by adding the varietal name, giving you 

Quercus 

garryana breweri

.