| 1 | Inflorescences composed of umbelliform cymes. |
| 1' | Inflorescences composed of peduncled disciform capitula. |
| 2 | Flowers sessile or subsessile in dense clusters |
| 2' | Flowers pedicellate. |
| 3 | Inflorescences verruculose; peduncles of cymes arising retrorsely from main axis. Leaf-margin with wide, shallow crenations; petiole inserted 2-3 mm from base |
| 3' | Inflorescences glabrous, papillose or puberulous; peduncles of cymes not retrorse along main axis. Leaf-margin not widely crenate; petiole inserted more than (6-)10 mm from base. |
| 4 | Leaves submembranous, margin often slightly lobed, reticulation scarcely raised and usually drying reddish brown. Inflorescence usually a solitary axillary subumbel |
| 4' | Leaves papyraceous to coriaceous. |
| 5 | Inflorescences less than 1.5 cm long. Reticulation on lower surface of leaf very fine and raised |
| 5' | Inflorescences 3 cm or more long. |
| 6 | Sepals unequal. Petals papillose-puberulous within. Upper surface of leaf often minutely subpapillose (large epidermal cells) |
| 6' | Sepals ± equal. Petals glabrous. Upper surface of leaf not subpapillose. |
| 7 | Leaves with lax reticulation. |
| 7' | Leaves with very fine reticulation. |
| 8 | Leaves triangular-orbicular to orbicular, apex rounded to very broadly obtuse |
| 8' | Leaves triangular to ovate, apex acute to obtuse. |
| 9 | Umbelliform cymes 2-5 cm with primary rays less than 1 cm. Leaves ovate to ovate-triangular, apex obtuse |
| 9' | Umbelliform cymes 4-14 cm with primary rays more than 1 cm. Leaves triangular to narrowly triangular, apex very acute |
| 10 | Leaves 5-9 by 4-8 cm. Inflorescences axillary, composed of very slender umbelliform cymes 2.5-6 cm long |
| 10' | Leaves usually more than 16 by 10 cm. Inflorescences very large (over 30 cm long) usually on old, leafless stems, composed of stout umbelliform cymes over 10 cm long |
| 11 | Leaves with a lax and rather obscure reticulation, apex often caudate; petiole inserted more than 10 mm from base |
| 11' | Leaves with a close, raised reticulation, apex shortly acuminate; petiole inserted 3-7 mm from base |
