| 1 | Hypanthium 7-10 cm long |
| 1' | Hypanthium up to 4 cm long |
| 2 | Buds small, globose, ovoid, ellipsoid, c. 5-10 mm long, or narrowly fusiform 10-12 by 2-3 mm; calyx splitting into 2-4(-5) ovate lobes, tardily caducous; anthers 1-3 mm long |
| 2' | Buds large, c. 8-50 by 4-10 mm long, ovoid, ellipsoid, obovoid, fusiform or cla- vate; calyx splitting into 5 (rarely 4) finally free, strap-shaped lobes, sometimes early caducous; anthers (3-)4-25 mm long |
| 3 | Ovary entirely glabrous; hypanthium long, thin, tubular, 10-20 mm long, longer than bud |
| 3' | Ovary hairy or puberulous; hypanthium short, turbinate or tubular, 2-6 mm long, shorter than or equal to bud |
| 4 | Lamina deeply divided nearly to the base; hypanthium c. 20 mm long; pod small, c. 12 by 1.5 cm |
| 4' | Lamina divided 1/3-1/2; hypanthium 10-15 mm long; pod large, 18-25 by 3-5.5 cm |
| 5 | Claw of petals distinct, 10-25 mm long, longer than or equal to limb |
| 5' | Claw of petals indistinct or short, shorter than limb |
| 6 | Bud ovoid-ellipsoid; petals with suborbicular limb |
| 6' | Bud narrowly fusiform; petals with lanceolate limb |
| 7 | Lamina entire, emarginate or bifid; flowers bright yellow, orange to red |
| 7' | Lamina bifid; flowers white, pinkish or yellowish |
| 8 | Ovary hairy only on stipe and along the sutures 25. |
| 8' | Ovary entirely hairy |
| 9 | Partial inflorescence a lax raceme; pedicel filiform, finally reflexed; filament hairy |
| 9' | Partial inflorescence a dense corymb; pedicel slender, not reflexed; filament glabrous |
| 10 | Petals 10-22 mm long, claw distinct, limb obovate; style glabrous |
| 10' | Petals 7-10 mm long, narrowly spathulate, claw indistinct; style hairy on lower part |
| 11 | Bud including hypanthium fusiform, 4-5 cm long; stigma indistinct or small capitate; anthers 20-25 mm long; petals early caducous; inflorescence a narrow raceme, 20-40 cm long |
| 11' | Bud ovoid, ellipsoid, obovoid or clavate, up to c. 3.5 cm long; stigma capitate, peltate, small to very large; anthers (3-)4-22 mm long, inflorescence a raceme, subcorymb or corymb |
| 12 | Leaves 6-8 cm long, 9-11-nerved; petals subglabrous outside. |
| 12' | Leaves larger, 14-25 by 10-22 cm, 11-15-nerved; the petals densely hairy outside |
| 13 | Bracts 15-25 mm long; stipe reddish pubescent |
| 13' | Bracts 2-3 mm long; stipe glabrous |
| 14 | Petals recurved; filaments 5-6 cm; stipules large, ± orbicular, 10-20 mm across |
| 14' | Petals not recurved; filaments short or long; stipules smaller, if large then lanceolate |
| 15 | Pedicels very short, 2-8 mm |
| 15' | Pedicels longer, 10-70 mm |
| 16 | Hypanthium long, 35-40 mm |
| 16' | Hypanthium shorter, 4-10 mm |
| 17 | Leaves small, 2-5 cm long, bifid 1/3-2/3; inflorescence axis ± elongate, slender; petals sparsely hairy outside |
| 17' | Leaves larger, (4-)5-8 cm long, bifid 1/4-1/2; inflorescence short, pyramidal, axis stout; petals densely hairy outside |
| 18 | Leaves suborbicular, lower reddish velvety; the hypanthium cup-shaped, c. 5 mm long |
| 18' | Leaves ovate-oblong, lower brownish woolly; the hypanthium tubular, 7-10 mm long |
| 19 | Leaves entire |
| 19' | Leaves bifid |
| 20 | Stipules large, lanceolate, 2-3 by 1 cm; sepals densely hairy both sides |
| 20' | Stipules smaller; sepals glabrous or sparsely puberulous inside |
| 21 | Stigma small, capitate, 1-2 mm across |
| 21' | Stigma large, peltate, 3-5 mm diam |
| 22 | Leaves large, (8-)10-26 cm long, tip of lobes acute to acuminate |
| 22' | Leaves smaller, 6-10 cm long, tip of lobes acute, subacute or obtuse |
| 23 | Inflorescences with brownish pubescence; flowers white; filaments c. 35 mm |
| 23' | Inflorescences ferrugineous pubescent; flowers yellow to scarlet; filament 5-7 mm |
| 24 | Bud large, 2.5-3 cm long, with 10 prominent longitudinal ridges |
| 24' | Bud smaller, up to 2 cm long, without ridges |
| 25 | Buds usually 2-3.5 cm long; petals densely hairy outside.. |
| 25' | Buds not over 1-2 cm long, rarely longer; petals glabrous to hairy outside |
| 26 | Hypanthium narrowly tubular, tapering to pedicels, 10-35 mm |
| 26' | Hypanthium tubular, with ± truncate base, 5-15 mm |
| 27 | Hypanthium dilated at base |
| 27' | Hypanthium not or only faintly dilated at base |
| 28 | Hypanthium ± urceolate, c. 5 by 4 mm. |
| 28' | Hypanthium tubular, 10-15 by 1-3 mm |
