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''Lactuca serriola'', also called prickly lettuce,〔(【引用サイトリンク】 publisher = USDA )〕 milk thistle〔 (not to be confused with ''Silybum marianum'', also called milk thistle) compass plant,〔 and scarole,〔 is an annual or biennial plant in the dandelion tribe within the daisy family. It has a slightly fetid odor and is commonly considered a weed of orchards, roadsides and field crops. It is the closest wild relative of cultivated lettuce (''Lactuca sativa'' L.). ''Lactuca serriola'' is known as the compass plant because in the Sun the upper leaves twist round to hold their margins upright. ''Lactuca serriola'' is native to Europe, Asia, and north Africa, and has become naturalized elsewhere.〔〔(Flora of North America, ''Lactuca serriola'' Linnaeus, Cent. Pl. II. 29. 1756. )〕〔(Flora of China, ''Lactuca serriola'' Linnaeus, 1756. 野莴苣 ye wo ju )〕〔(Flora Italiana, ''Lactuca serriola'' L. ) includes photos, drawings, European distribution map〕〔Cabrera, A. L. 1978. Compositae. 10: 1–726. In A. L. Cabrera (ed.) Flora de la provincia de Jujuy. Instituto Nacional de Tecnología Agropecuaria, Buenos Aires〕〔(Atlas of Living Australia )〕 ==Description== ''Lactuca serriola'' has a spineless reddish stem, containing a milky latex, growing from 30 to 200 cm (12-80 inches). The leaves get progressively smaller as they reach its top. They are oblong or lanceolate, often pinnate and (especially for the lower leaves), waxy grey green. Fine spines are present along the veins and leaf edges. The undersides have whitish veins. They emit latex when cut. The flower heads are 11 to 13 mm (0.44-0.52 inches) wide, pale yellow, often tinged purple, with 12-20 ray flowers but no disc flowers. The bracts are also often tinged purple. It flowers from July until September. The achenes are grey, tipped with bristles. The pappus is white with equal length 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「Lactuca serriola」の詳細全文を読む スポンサード リンク
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