WEEDS OF THE THISTLE FAMILY. 



175 



mentioned on a preceding page. These two species are notable for 

 their yellow ray -flowers which in August often cover acres of low- 

 lands with a flood of golden glory, but are succeeded in November 

 by myriads of the 2-pronged seeds which clutch the clothing of 

 the hunter for a free ride to pastures new. Remedies : mowing be- 

 fore the flowers open ; drainage and thorough cultivation. 



144. HELENIUM AUTUMNALE L. Sneezeweed. Swamp Sunflower. (P. 



N. 2.) 



Stem rather stout, nearly smooth, narrowly winged, much branched 

 above, 1-4 feet high; leaves alternate, oblong or lanceolate, pointed, nar- 

 rowed to the sessile base, few-toothed, 2-5 inches long. Heads numerous, 



about 1 inch broad, long-stalked; recep- 

 tacle convex, naked ; involucre saucer- 

 shaped, its bracts linear, reflexed, densely 

 woolly; disk many-flowered, yellow, glo- 

 bose; rays 10-18, drooping, bright yellow, 

 pistillate and fertile, 3-5 toothed or cleft. 

 Achenes top-shaped, ribbed; pappus of 

 5-8 ovate pointed scales. (Fig. 134.) 



Common in low moist grass-lands, 

 borders of fields, swamps, roadsides, 

 etc. Aug.-Oct. One of the most 

 handsome of our yellow-flowered 

 Compositse and, with the bur- 

 marigolds and smartweed, competing 

 for possession of many a swamp area. 

 Remedies: drainage and cultivation; 

 repeated mowings. 



Sneezeweed, when dried and pow- 

 dered, causes violent sneezing when 

 Fig. 134. (After Chesnut.) inhaled and is sometimes used in 



medicine to produce that effect. The heads are often sprinkled 

 with bitter aromatic globules and the whole plant is more or less 

 acrid and poisonous, especially to cattle, sheep and horses, which 

 often die after eating it in quantity. Its symptoms are said to be 

 an accelerated pulse, difficult breathing, staggering, extreme sensi- 

 tiveness to touch and, if fatal, spasms and convulsions. 



GROUP 0. 



In this group of Composite weeds the one to several rows of 

 rays around the margin of the head are usually white, though some- 

 times pinkish or bluish. Here belong the weeds known as asters, 

 fleabanes or white-tops, yarrow, dog-fennel and ox-eye daisy. 



