1Corolla tube > 7 mm long
1'Corolla tube ≤ 7 mm long
2Inflorescence brown pubescent; calyx lobes brown pubescent
2'Inflorescence glabrous or white puberulent; calyx lobes normally glabrous
3Inflorescence axis longer than the subtending petiole; leaves dull ochre beneath when dry
3'Inflorescence axis shorter or as long as the subtending petiole; leaves not dull ochre beneath when dry
4Leaves with 1 or 2 intercalcated veins parallel to the secondary veins; stamens inserted in middle of tube
4'Leaves with obscure or scalariform tertiary venation; stamens inserted below middle of tube
5Corolla tube 28-30 mm long
5'Corolla tube 7.5-15 mm long
6Leaves glaucous beneath; corolla tube > 9 mm long, lobes > 12 mm long
6'Leaves not glaucous beneath; corolla tube < 9 mm long, lobes < 12 mm long
7Inflorescence brown puberulent
7'Inflorescence glabrous or sparsely white puberulent
8Corolla tube ≤ 3 mm long. — Java
8'Corolla tube > 3 mm long. — Borneo
9Inflorescence fasciculate and dense, peduncle shorter than subtending petiole
9'Inflorescence lax, peduncle longer than subtending petiole
10Corolla tube inflated and much wider than head in bud
10'Corolla tube inflated only around anthers, not noticeably wider than head in bud
11Leaves with distinct intercalcated veins between the secondary veins
11'Leaves with indistinct venation or with veins perpendicular to secondary veins and no intercalcated veins
12Leaves thickly coriaceous, tertiary venation clearly visible perpendicular to and connected between secondary veins; calyx lobes < 1 times as long as wide
12'Leaves papery to coriaceous, tertiary venation faint or obscure; calyx lobes > 1 times as long as wide
13Tertiary leaf venation largely obscure; leaves glaucous beneath; corolla lobes 3-3.7 mm long
13'Tertiary leaf venation clearly visible; leaves not glaucous beneath; corolla lobes 1.4-2.8 mm long
14Secondary veins in leaf almost straight with 1-3 intercalcated veins between; leaves dull above and beneath
14'Secondary veins in leaf strongly ascending or, if not, then without intercalcated veins and leaves shiny above
1518-30 flowers per inflorescence; leaves dull above, 1.4-2.8 times as long as wide
15'8-15 flowers per inflorescence; leaves shiny above, 2.3-3.8 times as long as wide