엉겅퀴속 Cirsium ADANS.

1. 잎에 결각 같은 톱니가 있다.

2. 두화는 밑으로 처져 있다.

  3. 꽃이 필 때 뿌리에서 돋은 잎이 없다.

    4. 꽃부리 통부의 좁은 부분은 다른 부분보다 1.5~2.5 배 정도 길다 ··························································526. 큰엉겅퀴

    4. 꽃부리 통부의 좁은 부분은 다른 부분보다 짧거나 같다  ·····································································527. 물엉겅퀴

  3. 꽃이 펼 때 뿌리에서 돋은 잎이 있고 줄기에 홈이 파인 능선이 있다 ····················································528. 도깨비엉겅퀴

2. 두화는 밑으로 처지지 않는다.

  5. 뿌리에서 돋은 잎은 꽃이 필 때 남아 있고 줄기에 세로 능선이 있다.

6. 잎의 결각편은 서로 겹쳐지고 총포의 밑은 잎으로 둘러싸였다·························································· 529. 바늘엉겅퀴

6. 잎의 결각편은 겹쳐지지 않고 잎이 총포를 둘러싸지도 않는다······························································· 530. 엉겅퀴

5. 뿌리에서 돋은 잎은 꽃이 필 때 사라진다      ················································································ 531. 동래엉겅퀴

1. 톱니가 없고 가장자리에 가시가 돋거나 때로 밑부분만이 갈라진다.

7. 잎은 선형 또는 피침형이다.

8. 표면에 털이 없다 ·············································································································· 532. 버들잎엉겅퀴

8. 표면에 겨같은 털이 있다 ······································································································· 533. 흰잎엉겅퀴

7. 잎은 난형, 타원상 난형 등으로 피침형이 아니다.

9. 잎은 밑부분만이 갈라진 것이 있다 ·····························································································534. 정영엉겅퀴

9. 잎은 갈라지지 않는다 ············································································································ 535. 고려엉겅퀴