To extend Evan's thought a bit, if there is going to be a category for "Flower Form", it would perhaps be more accurate to divide it into "Flower Type" and "Inflorescence Type" categories or something along those lines.
Flower Type is typically pretty simply divided into:
Single
Compound
There are quite a few inflorescence types:
Raceme
Spike
Thyse
Panicle
Umbel
Compound Umbel
Corymb
Cyme
Spathe
Plus probably a handful of others I forgot.
