PLATE 48. 

 WILD OATS, Avena fatua, L., var. glabrata, Petermann. 



Other Latin names: Avena fatua, L., var. glabrescens. Cosson, and 

 Avena strigosa, Schreb., of Canadian writers. 



(Noxious: Dom., Ont., Man., N.W.) 



Introduced. Annual, smooth, 2 to 4 feet high, growing in erect tufts. 

 Plant closely resembling in general appearance some varieties of cultivated 

 oats. Panicle loose and open, spreading in all directions, 6 to 12 inches long. 

 The empty glumes or outer pair of scales, which enclose the 2 to 3-flowered 

 spikelets, green, herbaceous and thin, as in the cultivated oats, both of aboxit 

 the same length. The flowering glumes or husks of the seeds [Plate 56, fig. 

 80 natural size and enlarged twice] hard and horny, bearing many short 

 stiff bristles particularly about the base, rounded on the back, tapering to a 

 slender papery divided tip, 7-nerved, the nerves roughened with minute 

 teeth, and the central one running out from the middle of the husk into 

 a stiff twisted bristle-like awn, nearly an inch long, which in the ripe seeds 

 is bent at a right angle a little below the middle. The 2 or 3 florets or oats 

 in a spikelet vary much in size and colour, the lowest one being much larger 

 than the upper ones. 



There are two varieties of the "Wild Oat found as grain-field weeds in 

 Canada. The type of the species, Avena fatua, L., which has rather larger, 

 darker brown and much more bristly oats, is found in the eastern provinces ; 

 and the variety glabrata, with smaller, smoother, gray or olive-brown oats, 

 with comparatively heavier kernels, is the prevailing form in the West. 

 The identification of the variety glabrata was kindly made for me by Prof. 

 C. V. Piper, of Washington, D.C. The White Wild Oats sometimes found 

 are merely albinoes of these two varieties and do not always come true from 

 seed. Carefully selected white oats under cultivation produced many dark- 

 seeded plants and dark seeds gave several white oats. Both the eastern and 

 western Wild Oats may nearly always be distinguished from cultivated oats 

 by their earliness and the marked irregularity of ripening their seeds, the top 

 oats frequently being ripe and shelling out long before the florets at the 

 bottom of the panicle are ripe. Wild Oats contain smaller kernels, have al- 

 ways awns and some bristles at the base. The slanting horse-shoe shaped 

 scar at the base of the seed is densely bristly, although these bristles are 

 easily broken off, as also, with less frequency, is the scar itself, sometimes 

 making the certain identification of some seeds difficult when found among 

 threshed grain . The plate igiven herewith of the variety glabrata was drawn 

 by Mr. Criddle from a plant found in Manitoba. When the par ides first 

 appear from the sheaths, they are nmch more contracted in form. 



Wild Oats may be found in flower by the end of June, and some seeds 

 are ripe by the middle of July. 



Propagation : By seeds only. Plants cut off when in flower throw up 

 secondary flowering stems very quickly. 



Occurrence : In all parts of the country, the seeds being widely dis- 

 tributed with all kinds of cereal grains and also carried from farm to farm 

 in imperfectly cleaned threshing machines. 



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