You can have one if you tell me (truthily) what proper certified biologists do when they want to talk about the plural of "genus". It's "generes" in Latin. I thought that sounded a bit fancy for your garden variety sentence, so I tried typing "genuses", but Mr Microsoft Autopedant told me I was a pustulent hillock upon the dorsal skin of good usage.
Here, by the way, is the context: "Darwin’s sketches of the branching relations between [plural of genus], species, and varieties are, as he knows, foundational to his articulation of how biological difference comes to be in all its plenitude."
N.B. chocolate frog may turn out to be a metaphor for extreme kudos.
N.B.B. Apologies for "comes to be in all its plenitude". Euphony schmeuphony.
UPDATE: I am a Latin fraud. It's actually "genera", not "generes". Good night, then.
UPDATE THE SECOND: Am, like, totally embarrassed by this post, but I'm leaving it up to dispel myths of my omniscience. Ahem.