Key to the identification of four closely related Argostemma species of Mindanao

1. Stem solitary; leaf base cordate or round, margin slightly sinuate; inflorescence> 6 flowered................................. A. arachnosum

- Stem branching; leaf base acute, margin entire; inflorescence <6 flowered .....................................................................................2

2. Leaf adaxially glabrous and abaxially pubescent................................................................................................................... A. mirae

- Leaf adaxially and abaxially pubescent..............................................................................................................................................3

3. Stipules broadly ovate, hairy; calyx lobes 4; corolla lobes 4, both surface glabrous....................................................... A. distichum

- Stipules oblong, glabrous; calyx lobes 5; corolla lobes 5, both surface pubescent..................................................... A. solaniflorum