Some are used only once, and never applied to any other plant. Some are used across many different genera. Worse yet, they have prefixes, suffixes, and different endings depending upon other criteria. I will try to show how some of the specific epithets that actually have an historic meaning are constructed. As for the rest, you just have to grin and bear it.
Prefixes are numerous both in the Latin and the Greek languages.
The prefix changes the meaning from purple to dark purple. New epithets are invented from time to time, and their meanings require a little guessing if you cannot find them in the references. And, in fact, this plant comes from such peaks that exist in Southwestern USA, notably from the States of New Mexico and Arizona. In my flatland garden, I am sure that it grows much taller than seen in its native habitat. Suffixes permit a wide variety of words to be formed from a single word.