12 



AMERICAN MEDICINAL BARKS. 



motion by the slightest breeze and to quiver and tremble almost continually, 

 which has given rise to some of the tree's common names, such as quaking asp, 

 trembling poplar, and quiverleaf. Early in spring, before the leaves are out, 



the drooping catkins appear, the stami- 

 nate (male) from 1* to 1\ inches long, 

 the pistillate (female) crowded and 

 longer. The capsules which follow 

 are conical in shape, pointed, and two- 

 valved (fig. 4). 



Description of bark. — This bark gen- 

 erally occurs in straight pieces from 

 about 2 to 5 inches long and about 

 one-fourth to one-half inch wide. The 

 outside is grayish and smoothish ex- 

 cept here and there where marked 

 with lenticels. The inner surface is 

 somewhat rough to the touch, light 

 colored to brownish. The fracture is 

 even, somewhat corky, and the odor 

 faintly aromatic. 



Collection, prices, and uses. — The 

 bark of the aspen, or white or Ameri- 

 can poplar, as it is often known in the 

 drug trade, is collected in spring, and 

 collectors are paid from about 1 to 4 

 cents a pound. 



Fig 



4. — Aspen (Popitlus tremuloides), leaves 

 and capsules. 



It is used for its tonic properties, and has also been employed in the treat- 

 ment of intermittent fever. 



As in the case of the willows, to which family (Salieacea?) the poplars belong, 

 the glucoside salicin is also obtained from the barks of the various species of 

 Populus. 



WHITE WILLOW. 



Salix alba L. 



Other common names. — Salix, common European willow, duck-willow, Hunt- 

 ington willow. 



Habitat and range. — The white willow has been introduced into this country 

 from Europe, and has sparingly escaped from cultivation. It occurs in wet soil 

 along streams from Pennsylvania northward to New Brunswick and Ontario. 



Description of tree. — This is a tree of very rapid growth, and attains quite 

 a size, sometimes 90 feet in height, with a trunk perhaps 6 feet in diameter. 

 There is a group of willows known as "crack willows," on account of the 

 brittleness of the twigs where they are attached to the branches, and the white 

 willow belongs to this group, as does the " crack willow," or " brittle willow," 

 (S. fragilis), mentioned farther on. All of the species described are members 

 of the willow family (Salicacere). 



The gray and rough-barked white willow has lance-shaped leaves, pointed at 

 the apex and narrowed at the base, and with saw-toothed margins. When 

 young, both sides of the leaves are covered with silky hairs, but as they mature 

 they become less hairy and are pale green on the lower surface, or covered with 

 a " bloom." 

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