KEY TO THE SPECIES

1Stamens arranged in 4 whorls (shown distinctly in flower buds) or appearing scattered (in open flowers)
1'Stamens arranged in 1 to 3 whorls.
2Stamens arranged in 3 whorls
2'Stamens arranged in 1 or 2 whorls.
3Stamens arranged in 2 whorls.
3'Stamens arranged in 1 whorl.
4Perianth base prominently cordate, in side view with 2 distinct auricles. Perianth of the (mature) flower, folded in side view, rounded in outline, c. 7 cm ø; sinus 1-1.5 cm deep. (Leaves unknown)
4'Perianth base obtuse or rounded (in side view).
5Leaf base distinctly cordate, the sinus rather narrow and the auricles or basal lobes often overlapping.
5'Leaf base obtuse, rounded, or cuneate.
6Flowers large; perianth up to c. 12 cm long when mature,
6'Flowers smaller; perianth less than 3 cm long when mature.
7Perianth c. 23 mm long, deeply 3-lobed; lobes triangular, inner surface densely covered with papillae and glandular hairs. Stamens with papillate filaments. Style lobes 18-20.
7'Perianth 8-10 mm long, shallowly or obscurely lobed; lobes nearly semi-orbicular or triangular, inner surface densely covered with (mainly hooked) hairs. Stamens with glabrous filaments. Style c. 12 lobes
8Leaves with hairs densely covering the whole lower surface, so the latter usually hidden; hairs bent at right angles near the base and parallel to the surface.
8'Leaves with hairs rather loosely or sparsely covering the lower surface, so the latter always visible; hairs irregularly spreading, curved or twisted.
9Hairs on the lower leaf surface appearing very thin in dry state and sticking together (resembling a layer of gelatine). Perianth lobes with the margin not reflexed at anthesis. Seeds flattened, boat- shaped, rather smooth
9'Hairs on the lower leaf surface appearing thicker and free from one another. Perianth lobes with the margin reflexed at anthesis. Seeds ± ellipsoid, triangular, strongly rugose.
10Flowers large; perianth up to c. 12 cm long when open
10'Flowers much smaller; perianth at most 4.5 cm long.
11Stamens 3 in the upper whorl, 9 in the lower. Style 2- or 3-lobed
11'Stamens 6-15 (-18) in the upper whorl, 9-15 (-24) in the lower. Style (4-) 5-19-lobed.
12Perianth shallowly or obscurely lobed, sometimes ± entire.
12'Perianth distinctly lobed, often divided to c. half or more of its length.
13Leaf venation loosely reticulated, veins or veinlets often parallel to one another. Inflorescences at the upper part of stem, in the axils of foliage leaves. Fruits twisted, 15-25 cm long, densely hairy
13'Leaf venation closely reticulated. Inflorescences near the base of stem, in the axils of bract-like, reduced leaves. Fruits straight, less than 10 cm long, sparsely hairy or almost glabrous
14Perianth tube cylindric (c. 1.5 cm long)
14'Perianth tube campanulate, short cupular, obscure, or 0.
15Leaves with distinctly pinnate, often rather evenly spaced nerves; venation closely reticulate (almost tesselate), prominent beneath
15'Leaves with 1 or 2 pairs of basal nerves and some lateral ones from the midrib, not evenly spaced; venation loosely reticulate, slightly elevated beneath.
16Leaves with the inner pair of basal nerves emerging from the base. Inflorescences at the upper part of stem, in the axils of foliage leaves.
16'Leaves with the inner pair of basal nerves emerging near the base or a few mm from it. Inflorescences at the basal part of stem or near the ground, in the axils of bracts or reduced leaves (almost cauligerous).
17Perianth campanulate, 15-25 mm long, contracted at the lower ⅓ and then erecto-patent, glabrous outside; lobes triangular, flat
17'Perianth short-cupular, 10-13 mm long, sparsely puberulous outside; lobes reniform, the margin reflexed at anthesis
18Perianth c. 15 mm long, lobed to c. ⅔ of the length
18'Perianth 25-45 mm long, lobed up to c. half of the length.
19Perianth lobes semi-orbicular, 10 by 15 mm, at apex subrounded or slightly apiculate
19'Perianth lobes triangular, 20-25 by c. 20 mm, at apex acuminate.
20Leaves with the inner pair of basal nerves extending to the apex, joined by predominantly rather close, transverse, parallel veins. Inflorescences corymbose or paniculate
20'Leaves with the inner basal pair of nerves extending usually to c. half, rarely more, of the length, joined by rather loose, transverse and reticulate veins. Inflorescences usually spicate or racemose.
21Plant bearing 1-5 (often 2 or 3) foliage leaves. Leaves densely tomentose or villous beneath especially when young. Inflorescences near the base of stem. Style lobes densely covered with (hooked) hairs at the apical part
21'Plant bearing many foliage leaves. Leaves pubescent or puberulous beneath. Inflorescences at the upper part of stem. Style lobes glabrous.
22Perianth lobes broadly rounded, c. 12 by 4 mm, emarginate. Stamens 9-12; connective not protrudeing beyond the anthers
22'Perianth lobes ovate to lanceolate, 8-15 by 5-8 mm, apex acute, acuminate, or obtuse. Stamens 6; connective protruding c. 0.5 mm beyond the anthers