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''Erigeron philadelphicus'', the Philadelphia fleabane, is a widespread North American plant in the daisy family. Also known as common fleabane, daisy fleabane, frost-root, marsh fleabane, poor robin's plantain, skervish,〔(''Erigeron philadelphicus''. ) United States Department of Agriculture NRCS Plant Guide.〕 and in the British Isles as robin's-plantain. It is native to North America and found there in nearly all of the United States and Canada.〔(Biota of North America Program 2014 state-level distribution map )〕 It is also introduced into Europe and Asia, considered an invasive weed in many places.〔(Altervista Flora Italiana, Cespica di Philadelfia ''Erigeron philadelphicus'' L. ) includes photos and line drawings〕 == Description == ''Erigeron philadelphicus'' is a herbaceous plant with alternate, simple leaves, on hairy stems. The flower heads are borne in spring in arrays of as many as 35 heads. Each head may sometimes contain as many as 400 pink or white ray florets surrounding numerous yellow disc florets. The blooms are less than one inch (2.5 cm) in diameter. The stem is hairy with rough hairs. The middle to lower leaves are heart shaped, and the plant is about tall. Its active growth period is from spring to summer (April to July). This plant grows on roadsides, in fields, in thickets, and in open woods.〔(Flora of North America, ''Erigeron philadelphicus'' Linnaeus, 1753. Philadelphia fleabane, vergerette de Philadelphie )〕〔Dickinson, T.; Metsger, G.; Hull, J.; and Dickinson, R. (2004) ''The ROM Field Guide to Wildflowers of Ontario''. Toronto:Royal Ontario Museum, p. 163. 〕 ;Varieties *''Erigeron philadelphicus'' var. ''glaber'' J.K.Henry - British Columbia *''Erigeron philadelphicus'' Linnaeus var. ''philadelphicus'' - most of species range *''Erigeron philadelphicus'' var. ''provancheri'' (Victorin & J. Rousseau) B. Boivin - Ontario, Québec; New York, Vermont 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「Erigeron philadelphicus」の詳細全文を読む スポンサード リンク
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