.460 202. CONVOLVULACEAE 



Sepals membranous or scarious, the inner much smaller than the outer, 

 enlarged after flowering. Corolla bell- or pitcher-shaped. Fruit i- 

 seeded. — Species 12. Tropics. (Under Breweria R. Br.) 



Prevostea Choisy 



1:6. (5.) Flowers in axillary racemes. Outer sepals much larger than the 



inner, together with the 3 bracteoles much enlarged in the fruit. Corolla 



small, deeply lobed. Anthers exserted. Disc cushion-shaped. Ovary 



i-celled. Ovules 2. Stigma i. Twining herbs. Leaves cordate. — 



Species 2. Madagascar Cardiochlamys Oliv. 



Flowers solitary or in axillary, sometimes raceme-like C3aiies, rarely in 

 terminal spikes or panicles. Ovules 4 or more 17 



17. Ovules numerous. Stigmas 2. Filaments curved ; anthers much ex- 



serted. Corolla entire. Flowers solitary. Trees. — Species i. Mada- 

 gascar. Yields timber. Humbertia Lam. 



Ovules 4 — 6. Herbs, undershrubs, or shrubs 18 



18. Pollen-grains smooth. Corolla usually gradually widened from below 



upwards and without well defined midpetaline areas. Anthers included. 



Ovules 4. [Tribe CONVOLVULEAE.] 19 



Pollen-grains spinous. Corolla irregularly widened, with 5 longitudinal 

 midpetaline areas limited by prominent nerves 26 



19. Ovary i-celled, sometimes with an incomplete partition 20 



Ovary 2-celled, rarely (Merremia) 4-celled 22 



20. Stigmas globose. Sepals lanceolate, unequal, not enlarged after flowering. 



Corolla bell-shaped, shortly lobed. Stamens unequal. Fruit one- 

 seeded, indehiscent. Prostrate herbs. Leaves lobed. — Species i. 



East Africa (Somaliland) . Hyalocystis Hallier 



Stigmas ovate or oblong, flattened. Fruit 4-seeded, 4-valved. ... 21 



21. Sepals unequal. Corolla bell-shaped, entire. Twining herbs. Leaves 



ovate-cordate. Bracts small. — Species i. Tropical and South-east 



Africa. {Shutereia Choisy) Hewittia Wight & Am. 



Sepals about equal. Corolla slightly lobed. Twining or prostrate herbs. 

 Leaves sagittate or hastate. Bracts large, leaf-like. — Species 5. 

 North, South, and East Africa. Some of them have edible root- 

 stocks or serve as ornamental or medicinal plants. (Under Convolvulus 

 L.) Calystegia R. Br. 



22. Stigmas filiform. Disc present. Corolla funnel-shaped without well- 



defined midpetaline areas. — Species 70. Some of them yield an 

 essential oil used in perfumer3' or serve as ornamental or medicinal 

 plants. " Bind-weed." (Including Rhodorrhiza Webb et Berth.) 



Convolvulus L. 

 Stigmas elliptic, disciform, or globose 23 



23. Stigmas elliptic or disciform. Disc indistinct or wanting. Corolla with 



well-defined midpetaline areas, blue, more rarely white or reddish. 

 Sepals not decurrent on the pedicel, usually subequal. Herbs or under- 



