a. 蝶形的, 蝴蝶的

Papilionaceous \Pa*pil`io*na"ceous\, a.
1. Resembling the butterfly.

2. (Bot.)
(a) Having a winged corolla somewhat resembling a
butterfly, as in the blossoms of the bean and pea.
(b) Belonging to that suborder of leguminous plants
(Papilionace[ae]) which includes the bean, pea, vetch,
clover, and locust.