상추속 Lactuca LINN.

1. 다년초로서 꽃은 남자색이고 관모는 오백색이며 수과는 다소 편평하고 부리가 극히 짧다 ······························· 774. 자주방가지똥

1. 2년초로서 꽃은 황색 · 홍색 · 자색이고 수과는 편평하다

2. 수과는 능선이 많고 꽃은 황색이다.

3. 식물체에 가시가 있다 ········································································································· 776. 가시고들빼기

3. 식물체에 가시가 없다.

4. 잎은 둥근 난형이며 밑부분이 줄기를 감싼다 ······················································································773. 상추

4. 잎자루가 있으며 수과는 부리와 더불어 길이 2.5-4mm 이다 ······························································772. 산씀바귀

2. 수과는 각 면에 능선이 1개씩 있다.

5. 잎은 갈라지며 수과는 길이 5-6mm 이고 총포편은 너비 2.5mm 이다 ····················································775. 왕고들빼기

5. 잎은 갈라지지 않는다 ········································································································· 777. 두메고들빼기