| 1 | Plants annual, without a woody base |
| 1' | Plants suffruticose, with a hard, woody base |
| 2 | Plant (almost) erect, glaucous; stigmas usually 2; middle flower of cyme not reaching top of joint; seeds with conical, short hairs |
| 2' | Main stems prostrate, branches erect, greenish or reddish; stigmas usually 3; middle flower of cyme almost reaching the top of joint; seeds with hooked, thin hairs |
