천남성속 Arisaema MART.

1. 꽃차례의 부속체는 길게 자라서 포 밖으로 나온다.

2. 잎은 2 개이며 꽃차례는 끝을 포함하여 포의 1.5 배 이하이다    ·································································468. 섬천남성

2. 잎은 1 개이며 꽃차례 끌은 밖으로 길게 나온다.

3. 잎의 정소엽은 다음 측소엽보다 매우 작다   ················································································469. 두루미천남성

3. 잎의 정소엽은 다음 측소엽과 같거니 크다. 꽃차례 부속체 밑 부푼 곳에 잔주름이 많다    ·····························470. 무늬천남성

1. 꽃차례의 부속체는 원주형 내지 곤봉상이며 포보다 짧다.

4. 잎은 1개이다.

5. 소엽은 5 개이고 화병의 길이는 1-6cm 이며 포는 길이 8-13 cm 이다   ···············································471. 넓은잎천남성

5. 소엽은 3-5 개 (10개 내외)이고 화병의 길이는 6-17cm 이며 포는 길이 8cm 정도이다    ···································472. 천남성

4. 잎은 2개이다.

6. 소엽은 3 개이며 끝이 실같이 가늘다    ···························································································473. 큰천남성

6. 소엽은 6 개 이상이다.

7. 포의 부속체는 원주형이며 끝이 좁아진다. 포는 녹색이지만 가장자리에 자주색 점이 있는 것도 있다  ··········474. 점박이천남성

7. 포의 부속체는 곤봉상이며 끝이 두상이고 포는 녹색이다   ······························································474+. 우산천남성