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''Senecio flaccidus'', formerly recorded as ''Senecio douglasii'' (in honor of the botanist David Douglas) member of the daisy family and genus ''Senecio'' also known as threadleaf ragwort (and threadleaf groundsel, bush senecio, creek senecio, shrubby butterweed, comb butterweed, smooth threadleaf ragwort, Mono ragwort, Douglas ragwort, Douglas groundsel, sand wash groundsel, felty groundsel, old man, yerba cana, squawweed or cenicillo) is a native of the southwestern Great Plains of North America. ==Description== Threadleaf ragwort is a fast-growing, short-lived (3 to 6 years) bushy perennial shrub growing to ; common in gravelly washes, dry creek beds, along roads and trails and mostly away from the coast.〔 ;Leaves and Stems: Branched and bushy, ''Senecio flaccidus'' gets its common name from its white, threadlike, bent and matted, tomentose leaves; alternate and deeply pinnated, divided into five to nine narrow linear segments, glabrous, having no hairs or projections, gray-green above, to long. The principal leaves often have auxiliary clusters of smaller leaves.〔 The stems are grooved and the branches are thin, herbaceous above and woody near the base.〔〔 ;Flowers: Showy flowering heads of yellow ray flowers, - across; eight to thirteen sterile rays, purplish brown disk florets that produce the seeds.〔〔 ;Seeds: Dicotyledon fruits; each a 1/8 inch (3 mm) long achene ribbed and hoary, covered with short white hairs.〔〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Senecio flaccidus」の詳細全文を読む スポンサード リンク
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