| 1 | Stipules fully amplexicaul (subg. Ferolia). |
| 1' | Stipules not fully amplexicaul (subg. Brosimum). |
| 2 | Blade densely puberulous on the reticulum beneath. |
| 2' | Blade almost glabrous beneath or pubescent on the primary vein only. |
| 3 | Epidermis of the petiole (when dry) peeling off. |
| 3' | Epidermis of the petiole (when dry) persisting. |
| 4 | Primary vein of the blade impressed above; venation of the stipules prominent, subflabellate-furcate. |
| 4' | Primary vein of the blade plane above; venation of the stipules inconspicuous |
| 5 | Inflorescences bisexual. |
| 5' | Inflorescences unisexual. |
| 6 | Blade (almost) glabrous beneath. |
| 6' | Blade puberulous or hirtellous beneath. |
| 7 | Blade usually broadest above the middle, smooth above, plane when dry. |
| 7' | Blade usually broadest in or below the middle, more or less scabrous above, usually folded when dry. |
