THE MOST IMPORTANT SPECIES. 



Table 9. — Chemical analyses of Asdepias speciosa. 



37 



No. 



Place of collection. 



Date of 

 collection. 



Part of plant 

 analyzed. 



Acetone 

 extract. 



Rubber 

 (benzene 

 extract). 



304 



365 

 370 



371 



388 

 399 



889 



991 



Manitou, Colo 



Vaca Valley, Calif 



Near Mtinitou, Colo. ' . . . 



Colorado Springs, Colo. * 



Fort Scott, Kans 



Ute Pass, Colo. 



Wichita, Kans 



Colorado Springs, Colo . . 



July 18 



Oct. 27 

 July 14 



..do.... 



Aug. 9 

 Aug. 20 



Sept. 2 



Leaves 



Stems . 

 Roots . 

 Leaves 

 Leaves 

 Stems. 

 Leaves 

 Stems . 

 Leaves 

 Leaves 

 Stems . 

 Leaves 

 Stems . 

 Latex . 



p. ct. 



13.9 



8.4 



9.9 



7.8 

 6.6 

 5.9 

 7.1 

 7.5 

 8.7 

 7.1 

 7.0 

 6.0 

 67.5 



p. ct. 

 0.99 

 0.14 

 0.41 

 3.0 

 1.6 

 2.6 

 1.4 

 0.19 

 2.1 

 2.6 

 0.7 

 3.0 

 0.47 

 2.1 



' A broad-leaf form. 



* A narrow-leaif form. 



Apocynum cannabinum (Indian Hemp) and A. ANDROSiEMiFOLiuM 

 (Spreading Dogbane). 



Description (of A. cannabinum). — Plant an erect perennial herb, 

 3 to 6 feet high ; roots connected by horizontal creeping rootstocks, a 

 single plant thus coming to occupy areas several feet across under 

 favorable conditions; stems several at a place or solitary, straight, 

 smooth, and usually without hairs, the bast yielding a fiber of fair 

 quality (p. 57) ; leaves numerous, except on the lower part of old stems, 

 opposite, short-petioled, elliptic, acute, 1.5 to 4 inches long, 0.5 to 1.5 

 inches wide, smooth, glabrous or puberulent in some varieties, veiny; 

 flowers pinkish, appearing in June, July, and August, small, in terminal 

 and lateral stalked cymose clusters, yielding a moderate amount of 

 nectar to honeybees; pods pendent, 2 on each recurved stalk, terete, 

 5 to 7 inches long, about 0.12 inch thick, smooth and without hairs, 

 maturing from July to September, the earlier ones often well formed 

 before the last flowers have fallen. (Family Apocynacese.) 



References.— Gr&y, Syn. Fl., 2» : 83, 1878. Dodge, U. S. Dept. Agr. Fiber Investig. Rept. 

 6: 46, pi. 5, 1894. Dodge, ibid., 9: 62, fig. 20, 1897. Britton and Brown, 111. FI., ed. 2: 22, 

 figs. 3378-3381, 1913. 



Distribution and ecology. — The Indian hemp is a common plant 

 throughout the United States and southern Canada. In altitudinal 

 range it extends from the warm plains of Florida and the valleys of 

 southern California to at least 6,000 feet in the western mountains, but 

 it is not known with certainty above the lower part of the yellow-pine 

 belt. It grows best in gravelly or sandy soil, sometimes where but few 

 other plants can grow, but it requires a fair amount of soil-moisture. 



The cultivation of Indian hemp would not be a difficult matter, since 

 it propagates abundantly, both by seeds, which are provided with tufts 



