거북꼬리속 Boehmeria JACQ.

1. 잎은 호생한다. 잎의 뒷면은 솜털로 덮여서 희다.

2. 가지와 잎자루에 긴 털이 밀생한다 ·································································································· 163. 모시풀

2. 가지와 잎자루에 짧은 털이 밀생한다······························································································ 164. 섬모시풀

1. 잎은 마주 달린다.

3. 반관목으로 가지가 많이 갈라진다 ······························································································· 165. 좀깨잎나무

3. 초본으로 대개 가지가 적거나 없다.

4. 잎은 끝부분이 결각상이다.

5. 잎은 중앙열편 밑이 좁아진다 ··································································································166. 거북꼬리

5. 잎의 중앙열편 밑이 좁아들지 않는다···························································································170. 개모시풀

4. 잎은 갈라지지 않거나 한두 번 갈라진 것이 있다.

6. 잎은 두껍고 표면에 작은 돌기와 잔주름이 많아 깔깔하다·································································168+. 떡모시풀

6. 잎은 갈라지지 않았다.

7. 암꽃 화피통에는 윗부분에만 짧은 누운 털이 있다 ············ 167. 긴잎모시풀(톱니와 꽃이 보다 작은 것을 섬거북꼬리라고 함)

7. 암꽃 화피통에는 짧은 털이 있고 위쪽의 것이 보다 길다.

8. 잎의 톱니는 거의 비슷하다  ······························································································· 168. 왕모시풀

8 톱니는 윗가장자리의 것이 보다 크다 ······················································································169. 왜모시풀