Southwestern Plants by Corolla Characteristics

These are galleries in which I've arranged plants by features of the corolla, including symmetry, connation of petals, number of petals, and color. Some distinctions are vague without going into greater terminological precision, so I try to list species in multiple places where confusion is likely; e.g., Chamaesyce albomarginata is listed as both apetalous and as having small flowers with white petals. The petaloid appendages of the involucre are not petals, but are easily mistaken for them.