at Wheatland, Uva, Badger and Orin Junction. The crop on the Elkhorn at Lusk, and on the Burlington at Newcastle, Moorcroft, Sheridan, Ranchester and Parkman was even more prolific. As these, the only points at which personal investigation was made, were all infected, it seems justifiable to suppose that the weed is found at most points upon all of these lines.

Prof. W. C. Knight, of this Station, reports it abundant at Casper and at various points upon the freight road between that point and Lander, viz: on Poison Spider Creek. At these points it has probably been introduced by seeds in the grain which the freighters have fed at the camping places along the trail.

METHODS OF DISPERSAL.

The Russian Thistle belongs to the class of weeds properly called Tumbleweeds. It is not a thistle at all, and has been so called only on account of its spines. It would have been more in keeping to have called it the Russian Tumbleweed.

Tumble weeds are plants which usually branch freely, assuming in the course of growth a somewhat spherical form. These plants are annuals, and when mature and dead the one comparatively slender root is easily snapped by the wind and the plant is set adrift, to be threshed over miles of prairie and plain by every storm. On treeless and fenceless areas they travel till worn out, and, as their seeds are not readily dislodged, the thousands* that each plant bears may be distributed over scores of miles. This, while true of all tumble weeds, is especially true of the Russian Thistle.

*A plant of average size, weighing when dry 3 or 4 pounds, it is estimated bears upwards of 30,000 seeds; while the largest, sometimes weighing 20 pounds when dry, bears 150,000 to 200,000 seeds.

But were this the only manner in which its seeds are scattered it would not be so bad, for there are some natural barriers which it would hardly cross. Hay and grain and seeds in general are sent from infected areas, bearing, perhaps, the one seed which serves to infect a new region. Stock cars in their hay and litter carry the seeds from State to State, as evidenced by the fact that almost invariably the points of first appearance are on railroad lines, particularly about stock yards and other places where cars are cleaned from time to time.

SPECIAL DANGER IN WYOMING.

The belief that Wyoming has more to fear from this weed than most of the other States is based upon the following facts: The Russian Thistle belongs to a family of plants, the Chenopodiaceae, of which we have many native representatives. In common with many of these it thrives in all soils, but seems even to be favored by a percentage of alkali. Drought is no hindrance to it; it matures a crop when all else fails.

Our large areas of unoccupied lands, treelees and unfenced, offer unobstructed and immediate dispersal.

While it is true that it is not able to establish itself in well sodded ground, it is equally true that the open and imperfect sod of many of our native grasses do not resist its encroachments. At several points along the railroads it was observed among Blue Stem and other grasses. Once established on the general range, where it is everybody's or nobody's business to destroy it, it will never be exterminated. Viewed from this standpoint then it cannot be attacked too soon while it is yet, chiefly at least, upon railroad lines and in and about our towns and villages.

DESCRIPTION.

Technical description is purposely omitted, for I take it that those who are particularly interested wish simply the easiest method of recognizing it. To this end I give the following excellent popular description by Mr. L. H. Dewey, as given in the bulletins to which I have previously referred. The detail figures in Plate II, from the same source, and plates* I and III, will enable any careful observer to recognize the plant.

*

"In May and June the seeds germinate, each sending up on a slender red stem two narrow green leaves about an inch long and somewhat similar in appearance to shoots of grass. Between these seed leaves a short stem soon appears bearing slender spine tipped leaves, which later produce branches in their axils (Plate II, Fig. b). ** Until dry weather begins the plants grow rather slowly, but they store up an abun dance of moisture in the succulent leaves and branches. During the dry weather in August the moisture disappears from the slender leaves and they wither and sometimes fall off. New shoots are formed which at first are short and densely crowded with spine pointed leaves less than half an inch long, but later elongate so that the leaves become separated at intervals of one-sixteenth to one-half inch (Plate II, Fig. a). Each leaf is accompanied by two bracts similar to the leaf itself, all spine tipped and projecting at almost right angles to the stem. A single, small, stemless flower grows in a cup-shaped depression formed by the bases of the two bracts. The outer parts, or perianth, of the flower are thin and paper-like in texture, spreading, when fully open, about onefourth inch, and are usually bright rose color (Plate II, Fig. d). If the flower is taken out and carefully pulled to pieces a small, pulpy, green, coiled body appearing like a minute, green snail shell will be found (Plate II, Fig. f). This is the embryo or miniature plant. As the seed ripens its coat becomes of a dull gray color, and at maturity the whole seed is about one-sixteenth of an inch in diameter, irregular in form, and of about one-half the weight of a flax or clover seed (Plate II, Fig. e).

During August and early September the plants become rigid throughout and increase rapidly in size, often growing 2 or 3 feet in height and 4 to 6 feet in diameter, forming a dense, bushy mass of spiny branches (Plates I, III, and Plate II, Fig. a). By the middle of September the exposed parts of the plants have usually changed in color from dark green to crimson or rose red. When the ground is frozen in November the entire plant, except the seed, dies. The root is broken by

*The frontispiece, Plate I, has kindly been loaned to this Station by the Ohio Station; and for the use of Plate III we are indebted to the Wisconsin Station.

the force of the wind and the plant is blown about by the wind as a tumbleweed."

ITS PERNICIOUSNESS.

The Russian Thistle has no good points worthy of consideration. Some claims have been made for it as a forage plant, but its value in that direction should have no weight whatever when it is understood that it has no advantage over many others with no noxious qualities. cannot be eaten by stock on the range except during the summer months (June and July), when other palatable feed is abundant.

In cultivated grounds it is a weed first, last, and all the time, robbing the soil and crowding out the crops. This is especially its history in grain fields, where it not only greatly reduces or exterminates the crop, but greatly impedes the process of harvesting, damages the machinery, and injures the horses' legs to such an extent as to form festering sores.

The large, rigid plants greatly interfere with all farm. operations, and the dry plants, when banked against fences, corrals and stock yards offer inviting pathways for chance fires.

METHODS OF CONTROL.

It is an annual, hence if plants are not allowed to produce seed it will soon be brought under control.

It is not difficult to kill; if plowed completely under or if cut down with a hoe it dies; if mowed off below all of its branches at proper times it will suffice. If cut or mowed after blossoming the seeds are often matured from the sap of the somewhat succulent stems, hence all plants approaching maturity must be burned to make sure that they will not distribute any seed.