1 | Leaf base long decurrent |
1' | Leaf base cuneate, rounded, or slightly cordate |
2 | Terrestrial |
2' | Epiphyte |
3 | Stem shorter than the leaves, decumbent, apex erect |
3' | Stem longer than the leaves, applied to the ground or rocks |
4 | Leaves strongly unequal in a pair |
4' | Leaves equal or subequal in a pair |
5 | Adventitious roots borne along a straight longitudinal line at and between nodes (like Hedera helix) |
5' | Adventitious roots borne only at nodes |
6 | Leaf blade < 6 cm long; flowers solitary |
6' | Leaf blade > 7 cm long; flowers in a large inflorescence |
7 | Stem lianescent and appressed to the support, or suffrutescent herb; flowers 1-3 per axil |
7' | Stem erect; flowers several in an axil |