Leaves simple and opposite

1. Palmate venation
A Palmate from above base (see drawing) and aromatic, leaves often serrate Asteraceae (Compositae)
B Palmate from base (see drawing), secondary veins ladder-like
  No adventitious roots, woody hooks Loganiaceae
2. Pinnate venation
A Glands on petiole or lamina
(a) Succulent leaves, adventitious roots, glands at base of lamina (see drawing) Schlegelia sp. (Bignoniaceae)
(b) Leaves not succulent, no adventitious roots, glands on petiole Malpighiaceae
B Latex
(a) Yellow / orange latex, secondary veins inconspicious or parallel Clusiaceae
(b) White latex, free flowering Apocynaceae / Asclepiadaceae
C Obscure venation and coriaceous / succulent leaves
(a) Yellow / orange latex Clusiaceae
(b) No latex, adventitious roots, glands at the base of the lamina (see drawing) Schlegelia sp. (Bignoniaceae)
D Interpetiolar stipules
(a) Elastic strings in lamina (Stipules caduceous, scar present) Hippocrateaceae
(b) No elastic strings Rubiaceae
E Serrate leaves
(a) Adventitiuos roots, leaves and stems succulent Gesneriaceae
(b) No adventitiuos roots, plant aromatic Asteraceae (Compositae)
F Elastic strings in lamina (see drawing), strings more conspiciuos in the midvein, sometimes difficult to see, often petiole green contrasting with the stem and / or leaf underside olive green Hippocrateaceae
G Conspiciuos hairs on lower side
(a) Glands on petiole or base of lamina Malpighiaceae
(b) No glands, white hairs on underside of leaf Trigoniaceae
H Scabrous (rough) leaves
(a) Rough on both sides
  (i) White latex Apocynaceae
  (ii) Leaves aromatic, veins 3-nerved from above base Mikania sp. (Asteraceae (Compositae))
(b) Rough on lower side
  (i) Petiole grooved, twigs greyish, base of lamina slightly asymmetric Petrea sp. (Verbenaceae)
  (ii) Petiole not grooved, distichious leaves, elastic strings at least in mid-veins Prionostemma sp. (Hippocrateaceae)
I Base of the stem nodes conspiciously swollen Gnetaceae