1	"Nectaries, if present, in a ring around the base of the ovary; stigmatic head not forming translators for pollen transport; pollen usually shed as monads; plants usually trees, shrubs or woody climbers, occasionally subshrubs"	2
1	"Nectaries produced from the corona; stigmatic head forming differentiated translators with a sticky end or consisting of a clip with 2 flexible arms; plants usually herbs, often with succulent stems, or herbaceous climbers, sometimes shrubs or woody climbers"	16
2	"Leaves alternate"	3
2	"Leaves opposite, subopposite, or whorled"	5
3	"Corolla lobes overlapping to the right in bud; seeds with a tuft of hairs at both ends; plants native"	"Adenium obesum"
3	"Corolla lobes overlapping to the left in bud; seeds without tufts of hairs; plants cultivated ornamentals"	4
4	"Corolla white to red, often with a yellow throat; leaves 3 cm wide or wider"	"Plumeria rubra"
4	"Corolla yellow; leaves 0.5-1 cm wide"	"Cascabela thevetia"
5	"Plants armed with paired spines"	"Carissa spinarum"
5	"Plants unarmed"	6
6	"Corolla lobes ending with a 3-7 cm long linear tail"	"Strophanthus mirabilis"
6	"Corolla lobes not ending in a long tail"	7
7	"Leaves mostly in whorls of 3; corolla lobes overlapping to the right in bud"	"Nerium oleander"
7	"Leaves opposite or, at some nodes, sub-opposite; corolla lobes overlapping to the left in bud"	8
8	"Plants climbers, usually with tendrils"	9
8	"Plants subshrubs, shrubs, or trees, without tendrils"	11
9	"Inflorescences of cymes grouped into long, terminal panicles; anthers keeled on the back; fruits pubescent"	"Ancylobothrys petersiana"
9	"Inflorescences of cymes grouped into short, contracted panicles; anthers not keeled; fruits glabrous"	10
10	"Petioles up to 7 mm long, pubescent; anthers about 1 mm long"	"Landolphia lirkii"
10	"Petioles mostly 8-14 mm long, glabrous; anthers 2-3 mm long"	"Saba comorensis"
11	"Plants subshrubs up to about 1 m tall; fruits of 2 cylindrical follicles about 2-4 cm long"	"Catharanthus roseus"
11	"Plants shrubs or trees, usually taller; fruits not as above"	12
12	"Leaf tips with a hard mucro; fruits 1-seeded berries"	"Acokanthera schimperi"
12	"Leaf tips without hard mucro; fruits not as above"	13
13	"Branchlets and leaves pubescent; corolla with a corona in the mouth of the tube; fruit of 2 cylindrical follicles 12 cm long or longer"	"Wrightia demartiniana"
13	"Branchlets and leaves glabrous; corolla without a corona; fruits of 2 fleshy mericarps up to 8 cm long or carpels united most of their length"	14
14	"Carpels united for almost all their length, forming a fleshy 2-celled fruit"	"Ephippiocarpa humilis"
14	"Carpels free or almost so, forming 2 fleshy mericarps"	15
15	"Inflorescences mostly in pairs in the axils of dichotomous branches; mericarps 5-8 cm long, several-seeded"	Tabernaemontana
15	"Inflorescences terminal; mericarps 1.1-2.7 cm long, with 2 seeds"	"Hunteria zeylanica"
16	"Staminal filaments free; pollen usually in tetrads, occasionally in pollinia, deposited onto a spathulate translator lying between adjacent anthers on the stigmatic head"	17
16	"Staminal filaments, when present, united into a tube or rind; pollen of each anther cell aggregated into 1 or 2 pollinia, the pollinia from adjacent cells attached directly or indirectly toa a single translator lying between the anthers"	23
17	"Corollas about 6 cm long, pink"	"Cryptostegia madagascariensis"
17	"Corollas much shorter, variously colored"	18
18	"Corollas with a distinct, campanulate tube"	19
18	"Corollas without a distinct tube, usually rotate"	21
19	"Coronas and gynostegia enclosed with the corolla tubes; corona lobes inserted at middle of the corolla tubes and gynostegia at the base of the tubes"	Cryptolepis
19	"Coronas and gynostegia inserted at the mouth of the corolla tubes and exposed"	20
20	"Corona lobes free from each other; pollen in tetrads"	"Raphionacme borenensis"
20	"Corona lobes fused into an annulus; pollen in pollinia"	Schlechterella
21	"Corona lobes without any swelling or dark midvein area, glabrous"	"Tacazzea apiculata"
21	"Corona lobes with a dark swelling at their bases, on the adaxial side, and/or hairy on the adaxial surface"	22
22	"Stamens glabrous"	"Buckollia volubilis"
22	"Stamens hairy"	Periploca
23	"Four minute pollinia attached to each translator; translators soft, pale; plants woody climbers of small shrubs"	"Secamone punctulata"
23	"Pollinia attached in pairs to each translator; translators hard, usually dark brown or black; plants usually herbs, often with succulent stems or climbing, sometimes shrubs or woody climbers"	24
24	"Leaves well-developed although sometimes only 3-4 mm long"	25
24	"Leaves absent or reduced to scales"	46
25	"Plants annual erect herbs with linear leaves"	"Conomitra linearis"
25	"Plants perennial herbs, shrubs, or climbers"	26
26	"Corolla tube well developed, more than 10 mm long, usually much longer than wide; corolla-lobes usually remaining united that the tips to form a cage-like structure"	Ceropegia
26	"Corolla tube less than 10 mm long, usually shorter than wide; corolla lobes not united at the tips"	27
27	"Plants shrubs, usually 2m tall or taller; leaves 7-26 cm long and 4-15.5 cm wide"	"Calotropis procera"
27	"Plants herbs or climbers, woody or herbaceous, or, if shrubs, the leaves much smaller"	28
28	"Plants erect herbs with annual stems from perennial rootstocks or subshrubs with woody bases"	29
28	"Plants climbers, woody or herbaceous, or small shrubs"	31
29	"Plants usually 50 cm tall or taller; stems and leaves with indumentum of more or less long, soft hairs; corona arising from the gynostegium"	Gomphocarpus
29	"Plants up to about 30 cm tall; stems and leaves with indumentum of short, stiff, spreading hairs; corona arising from the corolla tube"	30
30	"Leaf blades linear-lanceolate to ovate; flowers in sessile, 1-7(-11) flowered umbels; corolla tube up to 1 mm long"	Glossonema
30	"Leaf blades suborbicular to reniform; flowers in long-pedunculate umbels with up to 15 flowers; corolla tube 4-5 mm long"	"Odontanthera radians"
31	"Plants large, woody climbers"	32
31	"Plants slender, herbaceous climbers or small shrubs"	33
32	"Corolla lobes glabrous to sparsely pubescent on the outer surface; corona arising from the gynostegium only"	Marsdenia
32	"Corolla lobes densely pubescent on the outer surface; corona arising from the sinuses between the corolla loves"	Leptadenia
33	"Plants small shrubs, sometimes with twining younger branches"	34
33	"Plants herbs or subshrubs, climbing, scrambling, or decumbent"	37
34	"Corolla densely hairy on the inner surface; leaves softly pubescent"	"Stigmatorhynchus umbelliferus aff."
34	"Corolla glabrous or minutely pubescent on the inner surface; leaves glabrous or minutely pubescent"	35
35	"Corona lobes fused for at least half their length; latex white"	Cynanchum
35	"Corona of 5 separate lobes; latex clear"	36
36	"Corona lobes 0.3-0.4 mm long, strongly swollen towards the base; pollinia spreading to suberect; leaves usually well over 5 mm wide"	Tylophora
36	"Corona lobes about 0.75 mm long, flattened; pollinia pendent; leaves mostly more than 5 mm wide"	"Blyttia fruticulosa"
37	"Corolla about 2.5 cm in diameter, broadly campanulate, white, inner surface with purple veins"	Oxystelma
37	"Corolla much smaller, variously shaped and coloured"	38
38	"Latex clear"	39
38	"Latex white"	44
39	"Corolla tube much longer than the short, erect lobes"	"Goydera somaliense"
39	"Corolla tube much shorter than the usually spreading lobes"	40
40	"Corona forming a tube"	41
40	"Corona of staminal lobes only"	42
41	"Leaves tapering at the base, up to 2 cm long; corolla lobes about 1.5 mm long; follicles not winged"	Calcareophilum
41	"Leaves cordate at the base, at least 3.5 cm long; corolla lobes about 5 mm long; follicles winged"	"Schizostephanus alatus"
42	"Corolla lobes twisted; corona consisting only of inconspicuous scales; stigmatic head extended into a long appendage"	"Pleurostelma cernuum"
42	"Corolla lobes not twisted; staminal corona lobes conspicuous; stigmatic head not extended into a long appendage"	43
43	"Inflorescences on 1.5-2.5 cm long peduncles; corolla lobes 9-10 mm long; corona lobes of 2 parts, an upper spreading lobe and, immediately below, a slender reflexed tongue"	Tylophora
43	"Inflorescences sessile or almost so; corolla lobes 4-9 mm long; corona lobes not of 2 parts"	Pentatropis
44	"Corolla lobes ciliate; follicles usually paired, thin-walled, and covered with soft spines"	Pergularia
44	"Corolla lobes smooth; follicles usually single, thin-walled and smooth or thick-walled and tuberculate or with a few soft spines"	45
45	"Corona lobes fused for at least 1/2 the length of the corona; follicles thin-walled, smooth or keeled"	Cynanchum
45	"Corona lobes fused only at the base; follicles thick-walled, sparsely to densely covered with protuberances"	Pentarrhinum
46	"Corolla tube well developed, more than 10 mm long, usually much longer than wide; corolla-lobes usually remaining united that the tips to form a cage-like structure"	Ceropegia
46	"Corolla tube not as above, if much longer than wide the stems with prominent angles or rows of tubercles"	47
47	"Plants shrubs or small trees, not succulent; corona lobes about 0.3 mm long, arising from the sinuses between the corolla lobes"	Leptadenia
47	"Plants herbs, erect or scrambling, clearly succulent; corona arising from the gynostegium"	48
48	"Stems smooth, papillose, or striate, usually scrambling or twining"	49
48	"Stems with prominent angles or rows of tubercles"	50
49	"Latex white"	Cynanchum
49	"Latex clear"	Calcareophilum
50	"Stems withs (5-)6-20 rows of tubercles or angles, if 5-angled, the flowers globose with a small opening"	51
50	"Stems with 4-5 angles; flowers not as above"	52
51	"Stems 7-20-angled, the angles divided into distinct tubercles or tessellate; corolla rotate to deeply urn-shaped with erect to reflexed lobes (Echidnopsis in FoS)"	Ceropegia
51	"Stems (5-)6-angled, the angles only indistinctly divided in tubercles; corolla globose with inflexed lobes hidden within corolla tube (Pseudopectinaria in FoS)"	Ceropegia
52	"Tubercles with hard, sharply pointed tips; stem leaves absent; stems creeping; corolla (3-)6-12 cm in diameter, with short, recurved lobes (Edithcolea grandis in FoS)"	"Ceropegia sordida"
52	"Tubercles more or less blunt-tipped or ending in scalelike leaves; stems ascending to erect; corollas usually less than 3 cm in diameter, their lobes various"	53
53	"Stem surfaces markedly wrinkled to bullate or irregularly tessellate"	54
53	"Stem surfaces smooth or almost so"	55
54	"Stems globose, ovoid, or more or less elongate, obscurely to distinctly 4-angled, the surface irregularly tessellate (Pseudolithis in FoS)"	Ceropegia
54	"Stems elongate, obscurely 4-angled to almost cylindrical, the surface wrinkled to bullate (Rhytidocaulon in FoS)"	Ceropegia
55	"Stems unbranched, up to 12 cm tall and 6 cm think, 4-angled, the angles wavy and without teeth (Whitesloanea in FoS)"	"Ceropegia crassa"
55	"Stems not as above"	56
56	"Inflorescences originating near the base of the stems"	57
56	"Inflorescences originating from the upper part of the stems"	58
57	"Corolla without short teeth in the sinuses between the lobes; corona stipitate (Duvalia in FoS)"	Ceropegia
57	"Corolla with short teeth in the sinuses between the lobes; corona sessile (Huernia in FoS)"	Ceropegia
58	"Stems with irregular purple-brown streaks or blotches; tubercles prominent, conical, tapering to a fine point; inflorescences various but never terminal umbels"	59
58	"Stems without dark markings; tubercles poorly defined or, if prominent and tapering, then inflorescences terminal umbels"	60
59	"Corolla rotate; inner corona lobes each with a dorsal projection (Ballyanthus in FoS)"	"Ceropegia prognatha"
59	"Corolla more or less campanulate; inner dorsal lobes without dorsal projections (Orbea in FoS)"	Ceropegia
60	"Inflorescences terminal, umbel-like, the umbels sometimes pushed into a lateral position by growth of the stem"	Ceropegia
60	"Inflorescences appearing axillary or extra-axillary, of solitary flowers or 1-few-flowered raceme-like inflorescences along the elongated apical stem portions"	61
61	"Inflorescences raceme-like and growing along elongated apical stem portions; corollas not campanulate"	Ceropegia
61	"Inflorescences with 1(-2) flowers and originating near the stem tops; corollas campanulate"	Leptadenia