6 THE RUSSIAN THISTLE. 



of an inch (2 mm.) long, the upper and two lower wings much broader 

 than the lateral ones; stamens five, about equaling the calyx lobes; 

 pistil simple; styles two, slender, about one twenty-fifth of an inch 

 (1 mm.) long; seed one, obconical, depressed, one sixteenth of an inch 

 (nearly 2 mm.) in diameter, dull gray or green, exalbuminous, the thin 

 seed-coat closely covering the spirally coiled embryo; embryo green, 

 slender, about one half inch (12 mm.) long when uncoiled, with two 

 linear cotyledons. The plant flowers in July or August, and the seeds 

 mature in September and October. At maturity, the action of the wind 

 causes the root to break with a somewhat spiral fracture at the surface 

 of the frozen ground, and the plant is blown about as a tumbleweed. 

 The mature flower with the inclosed seed is held in place by the minute 

 tufts of coiled hairs, preventing the seeds from falling all at once when 

 the plant begins to roll." 



This plant is especially well adapted to California conditions, and 

 should it once obtain a foothold here would prove the most serious of 

 any of our imported weed-pests. It is well adapted to our arid con- 

 ditions, maturing its seed early in the season, in readiness for the first 

 north wind to start it on its journey of seed-distribution. The plant 

 is a native of eastern Europe or western Asia, where it is as unfavorably 

 known as it is now in the Dakotas. It was first introduced in the 

 Dakotas in Bonhomme County, in flax seed imported from Europe in 

 1873. In a few years it increased with terrible and destructive rapidity, 

 until in 1892, Mr. Dewey, Assistant Botanist of the U. S. Department of 

 Agriculture, estimated that the cost to the farmers of Dakota alone in 

 loss of crops was over $2,000,000 for that season. In 1893 this estimate 

 was increased for the West to from $3,000,000 to $5,000,000, and this 

 has since been largely augmented by the greatly increased area subju- 

 gated by the pest. 



From a circular of Prof. L. H. Dewey, Assistant Botanist of the U. S. 

 Department of Agriculture, treating on the Russian thistle, we take the 

 following : 



"The injury to crops is of course the most important item in the 

 damage caused by the Russian thistle. It takes complete possession of 

 the land, crowding out other plants. Flax, wheat, rye, barley, and oats 

 all suffer from its effects, not only in the reduction of the crop but in 

 the lower grade of that which is harvested. Corn, potatoes, vegetables, 

 and, in fact, nearly all cultivated crops are injured more or less, pro- 

 portionately to their lack of care and cultivation. 



"The spiny character, added to the rigid, bushy habit of the plant, 

 makes it one of the most disagreeable of weeds to handle. When 

 mature it can not be plowed under, and it is often impossible to plow 

 fields at all until the thistles are removed. Binders can not be run 

 where the thistles are abundant, and even the working of the headers 



