까치수영속 Lysimachia LINN.

1. 잎은 대생 또는 윤생한다.

2. 줄기는 곧추 자란다

3. 꽃차례는 액생한다 ············································································································44. 버들까치수영

3. 꽃차례는 정생한다.

4. 잎은 검은 점이 흩어져 있거나 간혹 3~4개씩 윤생하고 뒷면 밑에 잔선모가 있으며 꽃받침잎 안쪽에 검은 줄이 있고 꽃잎에 황색 돌기가 있다 ········· 45. 좁쌀풀

4. 줄기에 능각이 있으며 잎 가장자리에 잔털이 산생하며 꽃잎 양면에 황색 털이 있다 ···································· 47. 참좁쌀풀

2. 줄기는 비스듬히 서지만 나중에는 옆으로 길게 받는다 ·············································································46. 좀가지풀

1. 잎은 호생한다

5. 꽃은 홍백색이다   ·····················································································································49. 섬까치수영

5. 꽃은 홍백색이 아니다.

6. 2 년초로서 육질이다   ··············································································································54. 갯까치수영

6. 다년초이다

7. 줄기에 능선이 있고 꽃은 드물게 달리며 소화병은 길다.

8. 잎은 좁고 너비 3~5mm 이며 둔두이다 .  ·················································································48. 물까치수영

8. 잎은 너비 1~4cm로서 예침두이다   ·······················································································49. 섬까치수영

7. 줄기는 둥글고 능선이 없으며 꽃은 밀생하고 소화병은 짧다

7. 꽃차례는 직생이고 전면에 꽃이 달리며 털이 없거나 선모가 있다   ·················································50. 진퍼리까치수영

9. 꽃차례는 편측생이며 다소 기울고 꽃대축에 털이 있다.

10. 잎은 둔두 또는 예두이고 너비 1~2cm 이며 줄기와 더불어 털이 갈색이다   ········································51. 까치수영

10. 잎은 예첨두이고 너비 2~5cm이며 줄기와 더불어 털이 있다   ······················································52. 큰까치수영