Key to the species of Eriosema in savannas of northern South America

1 Leaves unifoliolate .............................................................................................................................................................................2

- Leaves usually trifoliolate, but sometimes the basal ones unifoliolate ..............................................................................................3

2 Prostrate subshrub, stipules connate......................................................................................................................... E. simplicifolium

- Erect subshrub, stipules free............................................................................................................................................ E. obovatum

3 Stipules free and ovate.......................................................................................................................................... E. rufum var. rufum

- Stipules connate and lanceolate to broadly lanceolate .......................................................................................................................4

4 Stems yellow or rufous hirsute pilose ................................................................................................................................................5

- Stems densely whitish pubescent .......................................................................................................................................................7

5 Inflorescences spiciform, usually equal to or longer than mature leaves, multiflorous (10–20 flowers) ....................... E. violaceum

- Inflorescences in racemes, usually shorter than mature leaves, pauciflorous (2–5 flowers) .............................................................6

6 Stipules 3–7 mm long, leaflets (including terminal and lateral) usually 5 times longer than wide (1–3.5 x 0.25–0.5 cm)................. ....................................................................................................................................................................................... E. parvifolium

- Stipules 7–17 mm long, leaflets usually 6 to 12 times longer than wide (5–12 x 0.5–1.2 cm).................... E. crinitum var. crinitum

7 Leaflets elliptic, racemes with 5–15 flowers......................................................................................................................................8

- Leaflets lanceolate, linear or narrowly elliptic, racemes with 2–5 flowers................................................. E. crinitum var. stipulare

8 Inflorescences usually equal to or longer than mature leaves when fully expanded..................................................... E. pulchellum

- Inflorescences usually shorter than mature leaves when fully expanded.......................................................................... E. diffusum