Key for Brosimum Sw.

1Stipules fully amplexicaul (subg. Ferolia).
1'Stipules not fully amplexicaul (subg. Brosimum).
2Blade densely puberulous on the reticulum beneath.
2'Blade almost glabrous beneath or pubescent on the primary vein only.
3Epidermis of the petiole (when dry) peeling off.
3'Epidermis of the petiole (when dry) persisting.
4Primary 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
5Inflorescences bisexual.
5'Inflorescences unisexual.
6Blade (almost) glabrous beneath.
6'Blade puberulous or hirtellous beneath.
7Blade 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.