조팝나무속 Spiraea LINN.

1. 꽃은 희고 단순한 산형화서 또는 산형상 총상화서에 달린다.

2. 잎 가장자리 전체에 톱니가 있다.

3. 꽃은 묵은가지에 달리고 잎의 톱니는 단순하다.

4. 잎은 난형 내지 장타원상 피침형이다  ······················································································ 700. 조팝나무

4. 잎은 좁은 피침형이다 ································································································· 701. 가는잎조팝나무

3. 꽃은 새가지에 달리고 잎의 톱니는 겹이거나 결각상이다.

5. 수술은 꽃잎보다 길고 꽃받침잎은 열매가 자랄 때 뒤로 젖혀지며 꽃차례는 총상에 가깝고밑의 소화경은 떨어져 있다 ···················· 702. 인가목조팝나무

5. 수술은 꽃잎보다 짧거나 같고 꽃받침잎은 서지만 열매가 자랄 때 옆으로 퍼지며 꽃차례는산형이고 소화경은 밀생한다 ·························· 703. 공조팝나무

2. 잎의 하반부에는 톱니가 없다.

6. 잎의 톱니 끝은 둔하고 털이 없으며 맥이 뒤로 튀어나온다.

7. 잎은 도란형이며 대개 3출맥이 있고 톱니끝은 둥글다 ································································· 704. 산조팝나무

7. 잎은 장타원형이며 톱니는 물결형이다  ············································································· 705. 긴잎산조팝나무

6. 잎의 톱니끝은 뾰족하고 뒷면에 털이 있다.

8. 꽃차례와 열매에 털이 없고 잎은 타원형 또는 난상타원형으로 뒷면에 털이 밀생하며 수술은 꽃잎보다 짧거나 같고 꽃받침잎은 선다 ·············· 706. 아구장나무

8. 열매에 털이 있다.

9. 잎의 끝부근에 2~3 개의 톱니가 있다. 잎은 장타원형 또는 난상타원형으로 뒷면에 털이적고 맥이 튀어나오지 않으며 수술은 꽃부리보다 길다 ······ 707. 긴잎조팝나무

9. 잎은 원형 또는 난원형으로 톱니가 많다.

10. 잎은 두껍고 윤채가 나며 뒷면에 털이 밀생하고 맥이 튀어나온다   ··········································· 708. 떡조팝나무

10. 잎은 윤채가 없고 잔털이 있으며 뒷면에 황색 털이 있다   ······················································ 709. 당조팝나무

1. 꽃차례는 원추화서 또는 산방화서이다.

11. 꽃은 연한 홍색이고 원추화서에 달린다    ················································································· 710. 꼬리조팝나무

11. 꽃은 희거나 연한 홍색이고 산방화서에 달린다.

12. 잎은 밑에서부터 톱니가 있다.

13. 열매에 털이 없거나 복봉선에 따라 약간 있다.

14. 꽃차례 끝이 거의 평탄하다   ························································································ 711. 일본조팝나무

14. 꽃차례 끝이 볼록하다.

15. 가지에 줄이 있고 적갈색이다   ················································································ 713. 둥근잎조팝나무

15. 가지에 능각이 뚜렷하고 자갈색이다 ··············································································· 712. 참조팝나무

13. 열매에 털이 있다 ········································································································ 714. 덤불조팝나무

12. 꽃이 달린 가지의 잎에는 톱니가 없거나 1~2 개 있다 ································································ 715. 갈기조팝나무