34 



MISC. PUBLICATION 



XJ. S. DEPT. OF AGRICULTURE 



Description. — This tall forest tree, which at times attains a height of 110 feet 

 and a trunk diameter of 4 feet, is well known throughout its range as a source 

 of tanbark. Its lower branches are somewhat drooping, and the dense, rather 

 delicate foliage is deep green above and silvery beneath. The fiat, narrow 

 leaves are from one-half to three-fourths of an inch long and less than one-twelfth 

 of an inch wide. The hanging cones are as long as or slightly longer than the 

 leaves. 



Part used. — The bark. In limited demand onlv. 



Figure 61.— Hemlock (Tsuga 

 canadensis) 



Figure 62. — Hemp dogbane (Avocynum 

 cannabinum) 



HEMP DOGBANE 



Apocynum cannabinum L. (Fig. 62.) 



Other common names. — Black hemp, black Indian hemp, Canadian hemp, 

 American hemp, amy-root, bowmans root, bitterroot, Indian-physic, rheumatism 

 weed, milkweed, wild cotton, Choctaw-root. 



Habitat and range. — Hemp dogbane is a native of this country and may be 

 found in thickets and along the borders of old fields throughout the United 

 States. 



Description. — Hemp dogbane is from 2 to 4 feet high, with erect branches and 

 sharp-pointed, short-stalked leaves from 2 to 6 inches long. The small greenish 

 white flowers which appear from June to August are borne in dense heads followed 

 later by the slender, pointed pods which are about 4 inches in length. The 

 plant contains a milky juice. 



Other species. — The roots of a closely related species, Apocynum androsaemif- 

 olium L., are also collected. The branches of this plant are diverging and forked 

 and the flower heads loose and spreading. It also contains a milky juice. There 

 are several well-recognized forms which formerly were recognized as varieties 

 of A. cannabinum and A. androsaemifolium, but which are now considered 

 distinct species. The roots of all these species possess somewhat similar proper- 

 ties, but they are not all acceptable to the trade. 



Part used. — The root, collected in autumn, In reasonably constant demand. 



