3) 석곡족 Epidendrae

1. 꽃차례는 가지끝에 달린다.

2. 좌우로 편평한 잎은 2줄로 나열하며 꽃은 밑을 향하여 수상화서에 달린다 ···················································724. 차걸이난

2 잎은 전후로 편평하다.

3. 꽃은 꽃줄기끝에 1개 달리고 잎도 1개이다      ·················································································723. 풍선난초

3. 꽃은 여러개이다.

4. 꽃에 거가 있다.

5. 잎은 1개이고 순판은 3개로 갈라진다  ··················································································725. 비비추난초

5. 잎은 2개이상이고 순판은 갈라지지 않는다 ···················································································나리난초속

4. 꽃에 거가 없다························································································································727. 자란

1. 꽃차례는 곁가지에 달린다.

6. 잎은 눈안에서 포선상으로 접혀있다.

7. 화분괴는 4~8개로서 작은 꼬리가 있고 자루가 없다. 순판은 예주와 합생하며 허순판이 없다  ···························· 새우난초속

7. 화분괴는 4 개이며 작은 꼬리가 없고 자루가 있다. 순판은 예주의 밑부분과 붙거나 거를 만들고 하순판이 있다. 잎에 관절이 있다.

8. 순판은 길고 홈 안에 예주가 들어 있다.   ····························································································약난초속

8. 순판은 거나 포가 없고 예주를 감싸지 않는다   ·················································································738. 감자난

6. 잎은 어린 눈 안에서 안쪽으로 접혀 있다.

9. 화분괴에 부속체가 없고 때로 작은 꼬리가 있으며 기착식물이다.

10. 줄기는 가늘고 옆으로 자라며 꽃차례는 위구 밑에서 나온다   ································································콩짜개난속

10. 줄기는 총생하며 꽃차례는 끝에 달린다   ··························································································739. 석곡

    9. 화분괴에 돌기 또는 자루가 있으며 지상 또는 착생종이다      ·····································································742. 보춘화