| 1 | Leaves glossy above, usually less than 12 x 5 cm, lateral veins 15-25 per side, 3-4 mm apart |
| 1' | Leaves usually not glossy above, lateral veins mostly less than 15 per side, always more than 4 mm apart |
| 2 | Branches, petioles and leaf underside with ferruginous hairs (loupe) |
| 2' | Branches, petioles and leaves glabrous or nearly so, except the youngest parts |
| 3 | Hairs on vegetative parts spreading |
| 3' | Hairs on vegetative parts more or less appressed, minute |
| 4 | Leaves glabrous above |
| 4' | Leaves villous above, especially on midrib (Venezuela; see note to 3. Guapira kanukuensis) |
| 5 | Leaves drying brownish |
| 5' | Leaves drying blackish-brown (and see note to 3-3: Venezuelan Guapira amacurensis) |
| 6 | Leaves ovate, apex cuspidate-acuminate, often rufous beneath |
| 6' | Leaves elliptical, apex acuminate, not cuspidate, both sides same colour, usually 3 times as long as wide |
| 7 | Leaves elliptical, lateral veins obscure, 5-6 per side |
| 7' | Leaves often widest above middle, lateral veins prominent beneath, 8 or more per side |
| 8 | Leaves asymmetrical, midrib slightly curved |
| 8' | Leaves more or less symmetrical (incl. Guapira guianensis) |
| 9 | Lateral veins 8-10 per side, anastomosing 10-15 mm from margin, impressed above; tree cauliflorous (Venezuela; see note to 1. Neea constricta) |
| 9' | Lateral veins 10-18 per side, anastomosing less than 5 mm from margin, prominulous above |
| 10 | Lateral veins arcuate, smaller ones irregular, rather obscure; tree mostly cauliflorous |
| 10' | Lateral veins nearly straight to the loop with smaller ones in between, smaller veins distinct and prominulous beneath; tree not cauliflorous |
