메꽃과 Convolvulaceae

1. 기생식물로서 수술 밑에 인편이 있다 ·········································································································· 새삼속

1. 독립영양식물로서 수술 밑에 인편이 없다.

2. 암술머리는 얕거나 또는 깊게 2 개로 갈라진다 ····················································································155. 아욱메풀

2. 암술머리는 갈라지지 않는다 ················································································································· 메꽃속

3. 암·수술은 꽃안에 들어있다.

4. 꽃받침잎은 혁질이며 끝이 뾰족하고 씨방은 대개 3실이다  ······································································ 나팔꽃속

4. 꽃받침잎은 막질 또는 혁질이고 끝이 둔하거나 뾰족하고 씨방은 2-4실이다   ············································· 158. 고구마

3. 암·수술은 꽃밖으로 나와있다   ·········································································································· 유홍초속