Order 97.— ASCLEPIADS. 



287 



by the middle. Follicles long, slen- 

 der, separate. Seeds with a tuft of 

 long, silky down. Jime-Avgust. 



1 A. androsaeinifo''limn. Tutsan-leaved D. 

 Corolla rose-white, much longer than 

 the calyx. Leaves ovate. Plant 

 smooth, elegant, about 3f. high. 



5: A, cannabi'num. Hemp D. Cor. green- 

 ish-white, scarce longer, than the 

 calyx. Leaves oblong. Bark tough 

 as hemp. 



Fig. 620, Common Dog"s-bane. 1. A flower 

 of the natural size. 2. The flower cut open, 

 showing the peculiar stamens. .3. The 2 styles 

 and stigmas. 4. The plan of the flower. 5. Tho 

 2 follicles. 6. A seed with its tuft of silk. 





Order XCYII. ASCLEPIADACE^. Asclepiads. 



Plants (chiefly 116x1)8 in the United States) with a milky jwice; 

 leaies opposite (rarely whorled or scattered), entire, without stipules; 

 flowers generally umbeled, 5-parted, regular ; sepals and also the 

 petals united at base, both commonly valvate in the bud ; 

 stamens united into a fleshy mass with the two stigmas ; 

 pollen cohering in masses; ovaries 2, forming follicles in fruit 



Analysis of the Genera. 

 § Plants erect. Stamen-mass crowned with 5 little hoods.... 2 



§ Plants twining or prostrate 3 



2 Hoods each with a little projecting horn. . . .a 



2 Hoods destitute of horns b 



3 Flowers dark purple c 



3 Flowers whitish or flesh-colored 



■ Petals reflexed. Hoods erect, horns incurved. Silkgrass. MUkiceed. Ascle''pia8. 



b Petals reflexed. Hoods erect, adnate to the anthers. Acera'tes. 



. b Petals spreading, green. Hoods free from the anthers. S. Anan'therix. 



b Petals erect, yellowish. Mass of anthers stalked. S. Podostio'ma. 



