KEY TO THE GENERA Based on flowering material

1Inflorescences appearing before leaves or accompanied by some young ones (specimens collected from deciduous trees sometimes only consisting of bare inflorescences).
1'Inflorescences appearing at the same time as the leaves or accompanied by leaves.
2Calyx calyptriform. Stamens ∞
2'Calyx distinctly 4-lobed.
3Stamens or staminodes 8
3'Stamens or staminodes 4
4Leaves simple.
4'Leaves compound: uni- or trifoliolate, or imparipinnate, very rarely pseudoparipinnate or paripinnate.
5Leaves decussate
5'Leaves spiral, alternate, or sometimes subverticillate.
6Calyx calyptriform, at anthesis breaking away transversally at the base, often also bursting and opening irregularly, or splitting on one side
6'Calyx distinctly 5- or 4-lobed.
7Petals villous or woolly on the inner surface. Stamens with villous filaments.
7'Petals not villous or woolly on the inner surface, often glabrous, sometimes with thickened glandular ridges (Mangifera), or puberulous on the inner surface. Stamens with glabrous or very rarely papillose filaments.
8Carpels 4-6, free. Stamens usually 10, all fertile.
8'Carpels 1-3, united into a 1- or imperfectly 2-celled ovary. Stamens usually 5, sometimes 6-10 (-12, extra-Msd.).
9Anther cells not separate, dehiscing latrorse; connective not prolonged.
9'Anther cells separate, dehiscing introrse; connective prolonged, dilated and apically 2-lobed
10Stamens 6-10(-12), one to all of them fertile.
10'Stamens 5, one to all of them fertile.
11Flowers bisexual. Stamens 6-10, almost all equal in length and fertile. Ovary imperfectly 2-celled. Leaves often with dense or sparse, minute, peltate or lobed scales on both surfaces
11'Flowers ♂ and bisexual. Stamens (7-)10, unequal, 1-5 (rarely more) fertile. Ovary 1-celled. Leaves without the scales like above.
12Petals narrow-lanceolate to linear, 7-15 mm long. Leaves without hair-like fibers shown upon breaking
12'Petals elliptic or elliptic-oblong, oblong or oblanceolate, 4½-6 mm long. Leaves with hairlike fibers shown upon breaking
13Disk short-cupular, pulvinate, or stipe-like, distinct or obsolete, or consisting of 5 gland-like lobes and confluent with the base of filaments. Ovary with 1 style and/or 1 stigma.
13'Disk usually round, flat or slightly concave above, rarely short-cupular. Ovary with 3 styles and/or 3 stigmas (except 1 style and 1 stigma in Drimycarpus).
14Petals often with thickened glandular ridges on the inner surface. Stamens unequal, usually only 1 (rarely more) fertile (but all fertile in M. superba)
14'Petals without such glandular ridges on the inner surface. Stamens equal and all fertile
15Disk usually hairy; rudimentary pistil very small or 0 in ♂. Ovary usually hairy. Leaf beneath often papillose
15'Disk glabrous; rudimentary pistil distinct in ♂. Ovary glabrous. Leaf beneath not papillose, or rarely with rather compact papillae in Drimycarpus.
16Petiole O-½ cm. ♀ Flower with a superior ovary
16'Petiole 1½-2½ cm. ♀ Flower with an inferior ovary
17Flowers with one perianth whorl
17'Flowers with distinct calyx and petals.
18Stamens or staminodes the same number as the petals (4 or 5).
18'Stamens or staminodes twice the number as the petals (8 or 10).
19Flowers 4-merous. Disk hairy. Calyx accrescent
19'Flowers 5-merous. Disk glabrous. Calyx not accrescent
20Petals valvate. Leaflets with a distinct, continuous, intramarginal vein (except S. philippinensis)
20'Petals imbricate, at least at the apex. Leaflets without such intramarginal vein.
21Ovary 1-celled.
21'Ovary 5-12-celled.
22Terminal leaflet similar to the lateral ones. Stamens 10: 5 fertile and 5 staminodes. Ovary hairy
22'Terminal leaflet usually very small, reduced or not developed. Stamens in ♂ or bisexual flowers 10, all fertile. Ovary glabrous
23Leaflets 10-16 pairs, without domatia. (Ovary with incompletely connate carpels)
23'Leaflets (l-)3-9 pairs, often with hairy domatia (except Dracontomelon costatum).
24Ovary with incompletely connate carpels. Petals 4-10 mm long.
24'Ovary with completely connate carpels. Petals smaller, 1¼-3 mm long.
25Climbers. Disk c. 1 mm Ø. Stamens ¾-1 mm
25'Trees. Disk 1½-1¾ mmØ. Stamens 2-3 mm