432 100. GENTIANACEAE — 200. APOCYNACEAE 



21. Filaments with a double scale at the basei inserted at the middle of the 



corolla-tube. Anthers included, not twisted. Pollen-grains srrtooth. 

 Corolla-tube long. Stigma entire. Flowers small, in axillary* fascicles. 

 Herbs. — Species 3. Tropical and South-east Africa. Used medicinal- 

 ly. [Hippion Spreng.) Enicostemma Blnme 



Filaments without a scale at the base. Anthers usually exserted and 

 twisted after flowering. Flowers in usually lax cymes or solitary . 22 



22. Stigma 2-lobed or 2-parted. Pollen-grains medium-sized, smooth. Herbs. 



(See 10.) Erythraea L. C. Rich. 



Stigma entire. Pollen-grains very large, dotted. Corolla-tube rather 

 short 23 



23. Calyx with blunt, not keeled segments. Glands between calyx and corolla 



present. Corolla red. Stamens inserted at the throat of the corolla. 

 Hairy shrubs. Flowers large, in terminal cymes. — Species i. South 

 Africa (Cape Colony). Used as an ornamental plant. Orphium E. Mey. 

 Calyx with pointed, usually keeled segments. Glands between calyx and 

 corolla absent. — Species 40. South Africa, southern Central Africa, 

 and Malagasy Islands. Some species serve as ornamental plants. (In- 

 cluding Plocandra E. Mey.) (Plate 128.) . . . Chironia L. 



FAMILY 200. APOCYNACEAE 



Usually woody plants. Juice milky. Leaves entire, usually pe mi- 

 nerved with closely arranged, parallel primary side-ner.ves, generally opposite. 

 Flowers with bracteoles, usually panicled, regular or nearly so, 5-, very rarely 

 4-merous, hermaphrodite. Calyx imbricate in bud, usually deeply divided. 

 Petals united below, with contorted aestivation. Stamens as many as the 

 petals, inserted in the tube or at the throat of the corolla. Filaments free, short. 

 Anthers opening inwards by two longitudinal slits, sometimes adhering to the 

 stigma. Pollen granular. Ovary superior, more rarely half-inferior, i — 2- 

 celled, or 2, rarely {Pleiocarpa) 3 — 5 separate ovaries. Ovules 2 or more in 

 each cell, rarely solitary, pendulous, inverted. Style simple or divided at the 

 base, thickened at the apex, bearing the stigmas on the under-surfacc of the 

 .thickened part (stigmatic or stylar head), and sometimes two-lobed above it. 

 Seeds usually albuminous and provided with a wing or a tuft of hairs. — Genera 

 61, species 450. (Plate 12g.) 

 r. Stamens closely connected with the stigmatic head. Anthers prolonged 

 - at the base into empty tails. Corolla-lobes usually overlapping to the 

 right. Fruit dry, dehiscent. Seeds usually with a tuft of hairs. [Sub- 

 family ECHITIDOIDEAE.] 2 



Stamens free or loosely cohering with the stigmatic head. Anthers without 

 tails, full of pollen to the base, more rarely prolonged into tails, but then 

 fruit fleshy and most frequently indehiscent. Corolla-lobes usually over- 

 lapping to the left. Seeds usually without a tuft of hairs. [Subfamily 

 PLUMEROIDEAE.l 22 



