| 1 | Flowers sessile (capitate) or very shortly pedicelled. |
| 2 | Flowers sessile, underside of leaf ± densely tomentose, hairs of the branches and inflorescence ± appressed and felted, bracts around the capitula enveloped in hairs |
| 2' | Flowers short-pedicelled, underside of leaf sparsely tomentose, hairs of the branches and inflorescence ± patent, bracts around the capitula less densely tomentose |
| 2'' | Flowers 0.5-1.5 cm pedicelled (umbellate). |
| 3 | Climbing or scrambling liana, spines curved |
| 3' | Erect shrubs or small trees, spines straight. |
| 4 | Leaflets glaucous beneath, margins with few crenations. Fruit small (c. 3 mm long) |
| 4' | Leaflets green (or with fawn pubescence) beneath, margins serrate. Fruit rather larger (4-6 mm long). |
| 5 | Young parts and undersurface of leaves glabrous (but with small spines). |
| 5' | Young parts and undersurface of leaves pubescent |
