. A manual of weeds : with descriptions of all the most pernicious and troublesome plants in the United States and Canada, their habits of growth and distribution, with methods of control . Weeds. GOMPOSITAE (COMPOSITE FAMILY) 479 clusters; outer bracts of the invo- lucre eight to ten, linear or spatu- late, not exceeding the inner row; rays six to ten, broad, obtuse, bright golden yellow. Achenes obovoid, flat, rough-hairy, tipped with two (occa- sionally four) slender, diverging awns, sometimes as long as the achene itself or sometimes reduced to short teeth; the barbs on the awns and on the
. A manual of weeds : with descriptions of all the most pernicious and troublesome plants in the United States and Canada, their habits of growth and distribution, with methods of control . Weeds. GOMPOSITAE (COMPOSITE FAMILY) 479 clusters; outer bracts of the invo- lucre eight to ten, linear or spatu- late, not exceeding the inner row; rays six to ten, broad, obtuse, bright golden yellow. Achenes obovoid, flat, rough-hairy, tipped with two (occa- sionally four) slender, diverging awns, sometimes as long as the achene itself or sometimes reduced to short teeth; the barbs on the awns and on the sides of the achenes are on some directed downward, on others upward. (Fig. 332.) Means of suppression the 'same as for Bidens frondosa. TARWEED Mddia saAva, Molina. Fig. 332. — Western Tiekseed Sunflower (Bidens aristosa). XI. Introduced. Annual. Propagates by seeds. Time of bloom: May to October. Seed-time: June to November. Range: Pacific Coast from California to Washington. Habitat: Fields, roadsides, and waste places. A most unpleasant weed, covered with a viscid, ill-scented excre- tion which injures everything that it touches, from the crops among which it is harvested to the clothing of passers-by. None of the native Tarweeds are so offensive as this, which is an immigrant from Chile. A remarkably sweet and limpid oil is expressed from the seeds, good for table use and particularly valuable for a lubricant, as it does not readily congeal; in order to obtain this oil the plant is extensively cultivated in South America and in Europe*. Stem stout, one to four feet tall, finely hairy, beset with viscid, pedicel- late glands. Leaves alternate, entire, varying from broad lance- shape below to linear above, all sticky and strong-scented. Heads numerous, sessile or on short peduncles at the ends of the short branches and in the upper axils; they are about three-fourths of an inch broad, with eight to twelve pale yellow rays and darker Please note that these images ar
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectweeds, bookyear1919
