I am just a dumb inquisitive racher, The common names are good enough for me, still I can see the need to know the botanical names of plants. There are many common nanes sometimes used for the same plant, or there are some common names applied to entirely different plans.
I thinkl if you would try to find the meaning of the Latin word, maybe even the meaning of the prefix of the work, then see why it was used would help.
An examsle, Astragalus I believe referes to a star or stars, This is used as a name for the milkvetches. I can't see where there is a connection though.
Echinacea referes to a spiney sea unchin. The spinny head of the Prairie Coneflower.
Psoralea means scaley or blotchy. Indian Breadplant and the scurf peas or examples.