peristome
/ˈperɪstəʊm/noun
1- Zoology the parts surrounding the mouth of various invertebrates【动】（无脊椎动物的）口围, 围口部, 口缘。
1.1
- Botany a fringe of small projections around the mouth of a capsule in mosses and certain fungi【植】（藓类的）蒴齿（层）; （某些真菌的）子实竭。
词源
late 18th cent.: from modern Latin peristoma, from Greek peri- 'around' + stoma 'mouth'.