| 1 | Leaves deeply 3-lobed, in shape often resembling the letter 'W' |
| 1' | Leaves entire, very rarely remotely minutely toothed (A. philippinensis). |
| 2 | Leaf base obtuse or rounded, subacute, or cuneate. (Plants erect, up to c. 1 m high). |
| 2' | Leaf base distinctly cordate, sometimes slightly or shallowly cordate, very rarely associated with some obtuse ones (A. sericea). |
| 3 | Perianth with tube and limb bent backward and parallel to the utricle. Utricle 35 mm long, tube 10-15 mm long, limb 45 mm long. Seeds verrucose on both surfaces. Petiole 6-10 mm long |
| 3' | Perianth straight. Utricle 6-7 mm long, tube 5-15 mm long, limb 18-25 mm long. |
| 4 | Leaves glabrous on both surfaces. Petiole 4-8 (-20) mm long. Seeds verrucose beneath and marginal part above |
| 4' | Leaves glabrous above, sparsely short-hairy beneath. Petiole (20-) 30-40 mm long. Seeds verrucose only on the marginal part beneath, smooth above |
| 5 | Erect plants up to 1 m high. Petiole 2-10 mm long. |
| 5' | Twiners or climbers. Petiole 20-70 mm long. |
| 6 | Leaf base deeply cordate; auricles often overlapping or surrounding the stem. |
| 6' | Leaf base slightly or shallowly cordate, rarely associated with some obtuse ones; auricles obscure or 0 |
| 7 | Leaf veins and veinlets foveolate-reticulate, prominent beneath. Utricle with 6 (or 2) glandular bodies inside. Seeds not winged |
| 7' | Leaf veins and veinlets often loosely, rarely closely, reticulate, or transverse, distinct or rather faint beneath. Utricle with 2 glandular bodies inside. Seeds distinctly winged (not known in A. leytensis). |
| 8 | Leaf veins and veinlets (closely reticulate) densely covered with minute hairs beneath (handlens or binocular). Seeds (proper) verrucose on both surfaces |
| 8' | Leaf veins and veinlets (loosely reticulate) sparsely short-hairy or (nearly) glabrous beneath. |
| 9 | Perianth tube 20 mm long, limb 50-60 mm long. Mature seeds not known |
| 9' | Perianth tube 5-10 (-15) mm long, limb 20-30 (-40) mm long. Seeds verrucose beneath, less so above |
