tick trefoil
tick-trefoil的词性：
n.（名词）
1. Any of various plants of the genus Desmodium, usually having trifoliolate compound leaves, racemes of small purplish or white flowers, and jointed seedpods with easily separable, one-seeded segments.
山马蝗三叶：几种山马蝗, 属植物，生有三片的复叶及紫色或白色的头状花序，荚相连且每个荚有很容易分开并生有一粒种子的小室
tick-trefoil的词源：
2. From tick 2 [from the way its pods adhere to animals]
源自 tick2 [源于它的荚粘着在动物身上的方法]