SOLANALES.] 



ASCLEPIADACE.^. 



G23 



Order CCXXXIX. ASCLEPIADACEiE.— Asclepiads. 



Apoc}Tie», Juss. Gen. 143. (1789) in part.— Asclepiades, R. Brou-n in Wern. Trans. 1. 12 (ISOfl) ; 

 Prodr. 458. (1810) ; Roi/k lllustr. 272. (1835) ; Wight's Contributions to the Botany of India, No. 

 2. p. 77. (1834) ; Endl. Gen. cxxiii. 



Diagnosis.— /S'oZowa/ Exocjcns, with the anthers and stigma consolidated into a column. 



Shrubs, or occasionally herbaceous plants, almost always milky, and often twining. 

 Leaves entire, opposite, sometimes alternate or whorled, having cUise between then- pe- 

 tioles in lieu of stipules. Flow- j^ 

 ers somewhat umbelled, fasci- v 

 cled, or racemose, proceeding 

 from between the petioles. Ca- 

 lyx 5-di^^ded, persistent. Co- 

 rolla monopetalous, hypogynous, 

 5-lobed, regular, with imbricated, 

 very seldom vahnilar, aestiva- 

 tion, deciduous. Stamens 5, in- 

 serted into the base of the co- 

 rolla, alternate with the segments 

 of the limb. Filaments usually 

 connate. Anthers 2-celled, 

 sometimes almost 4-celled in 

 consequence of their dissepi- 

 ments being nearly complete. 

 Pollen at the period of the de- 

 hiscence of the anther cohermg 

 in masses, either equal to the 

 number of the cells, or occa- 

 sionally cohering in pau's and 

 sticking to 5 processes of the 

 stigma either by twos, or fours, 

 or singly. Ovaries 2 ; styles 2, 

 closely approaching each other, 

 often very short ; Stigma com- 

 mon to both styles, dilated, 5- 

 cornered, with corpusculiferous 

 angles. FoUicles 2, one of which 

 is sometimes abortive. Placenta 

 attached to the suture, finally 

 separating. Seeds nmnerous, 

 imbricated, pendulous, almost 

 always comose at the hilum. 

 Albumen thin. Embryo straight. 

 Cotyledons foliaceous. Radicle 

 superior. Plumule inconspi- 

 cuous. 



For a longtime the real struc- 

 ture of the present Order was 

 misunderstood ; but Brown, in 

 a Dissertation in the Transac- 

 tions of the Wernerian Society, 

 placed its time nature beyond doubt. I subjoin the explanation given by this celebrated 

 Botanist, who thus describes the flower of Asclepias sjTiaca : — 



" The flower-bud of this plant I first examined while the unexpanded corolla was yet 

 green and considerably shorter than the calyx. At this period the gland-Ukc bodies 



Fig. CCCCXIX 



Fig. CCCCXVIII.— Seed and embryo of Vincetoxicum nigrum. ri^c^ 



Fig. CCCCXIX.— 1. flower of Cynanchum fruticulosum ; 2. its pollen masses ; 3. column oi ^''Ofso- 



nema Boryanum ; 4. flower of Heterostemma acuminatum ; 5. one of its anthers ; 6. its pouen masses , 



7. Asterostemma repandum ; 8. its coronet ; 9. its pollen masses.— i't'caijw. 



