THE RUSSIAN THISTLE. 



The whole plant is horn.' upon a single, short, slender stem, half an 

 inch or less in dimmer, which, when the plant ripens, dries and becomes 

 very brittle. Under pressure of the first hard wind, it snaps off, and the 

 l goes bounding along before the wind, distributing the seeds in 

 y direction. In Dakota, specimens which had been tagged were 

 traced for a distance of from 10 to 15 miles, so it will be readily under- 

 stood that a single plant may be the cause of infesting a very large area 

 of territory in a few seasons, and the necessity of extirpating every 

 specimen on sight will be appreciated. 



The seed is described as quite small, of rather peculiar shape, and the 

 whole space inside the coat is occupied by the embryo or young plant, 

 there being no albumen, as is the common condition in the grains. 

 After the plant is mature, the branches lose their red and green color 

 and become dry and bleached in appearance. The root, which is at no 

 time very well developed, then breaks off near the surface and the 

 plant is ready to start on its seed-scattering journey before the wind. 

 And it is well suited to this mode of transportation. It is light, wiry, 

 and strong; its shape is pretty nearly that of a sphere, and it goes 

 bounding across fields until it is stopped by a fence or a ditch or vegeta- 

 tion, leaving its seeds scattered over miles of surface, ready to sprout 

 as soon as favorable conditions shall arise. 



The following technical description is taken from Bulletin No. 15, 

 Division of Botany, U. S. Department of Agriculture, by L. H. Dewey : 



~s,,ls<>1., l-nli tragus (L.) Moq. in D. C. Prod., XIII, 2, 187 (1849). 

 A herbaceous annual, diffusely branching from the base, 1% to 3 feet 

 (0.5 to 1 m.) high and twice as broad, smooth or slightly puberulent; 

 tap root dull white, slightly twisted near the crown; leaves alternate, 

 sessile; those of the young plant deciduous, succulent, linear or sub- 

 terete, 1 to 2 inches (3 to 6 cm.) long, spine-pointed, with narrow, 

 denticulate, membranaceous margins near the base ; leaves of the mature 

 plant persistent, each subtending two leaf-like bracts and a flower at 

 intervals of one twelfth to five twelfths of an inch (2 to 10 mm.), rigid, 

 narrowly ovate, often denticulate near the base, spine-pointed, usually 

 striped with red like the branches, three twelfths to five twelfths of an 

 inch (6 to 10 mm.) long; bracts divergent, like the leaves of the mature 

 plant in size and form; flowers solitary and sessile, perfect, apetalous, 

 about five twelfths of an inch ( 10 mm. ) in diameter ; calyx membrana- 

 ceous, persistent, inclosing the depressed fruit, usually rose-colored, 

 gamosepalous, cleft nearly to the base into five unequal divisions, about 

 one sixth of an inch (4 mm.) long, the upper one broadest, bearing on 

 each margin near the base a minute tuft of very slender coiled hairs, the 

 two nearest the subtending leaf next in size, and the lateral ones narrow, 

 each with a beak-like connivent apex, and bearing midway on the back 

 a membranaceous, striate, erose-margined horizontal wing one twelfth 



