수련과 Nymphaeaceae

1. 종자에 배유가 있다.

2. 씨방은 이생이다  ····························································································································352. 순채

2. 씨방은 전부 또는 일부가 합생한다.

3. 꽃받침잎은 5개이며 종자에 가종피가 없다  ··························································································개연꽃속

3. 꽃받침잎은 4개이며 종자에 가종피가 있다.

4. 씨방상위이며 꽃부리와 수술은 씨방에 달리고 식물체에 가시가 없다  ······················································· 356. 수련

4. 씨방하위이며 전주에 가시가 있거나 잎이 실처럼 갈라친다.

5. 잎은 갈리지지 않고 가시가 있다  ····························································································355. 가시연꽃

5. 잎은 잘게 감라지고 가시가 없다  ····························································································358. 어항마름

1. 씨방에 배유가 없다 ··························································································································· 357. 연꽃

개연꽃속 Nuphαr SMITH

1. 잎은 장란형 내지 장타원형이며 물 위에 나오고 뒷면 주맥에 털이 약간있다  ····················································· 353. 개연꽃

1. 잎은 넓은 난형, 난상 원형 내지 타원형이며 물에 뜨고 뒷면에 잔털이 밀생한다  ·············································· 354. 왜개연꽃