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Published In: Tableau de l'École de Botanique 89. 1804. (Tabl. École Bot.) Name publication detailView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 8/11/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Introduced

 

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2. Picris rhagadioloides (L.) Desf. (bitterweed)

P. altissima Delile

Pl. 260 n–o; Map 1089

Plants annual, taprooted. Stems 20–100 cm long, moderately to densely pubescent with spreading, barb-tipped hairs, usually also sparsely to moderately pubescent with minute, appressed, branched hairs. Basal and lower stem leaves 3–15 cm long. Involucre 7–12 mm long, the inner series of bracts thickened and hard at fruiting, the basal portion becoming wrapped around the outer series of fruits (these usually becoming dispersed tardily, remaining with the involucre after the inner fruits have been shed), pubescent with a central band of spreading, barb-tipped hairs, usually also pubescent with sparse to moderate, minute, appressed, branched hairs. Corollas 0.8–1.5 cm long. Pappus 4–6 mm long (that of the outer florets sometimes shorter elsewhere). Fruits 2.5–3.0 mm long. 2n=10. June–September.

Introduced, known thus far only from St. Louis County (native of Europe, Africa; introduced). Railroads.

The correct name for this plant remains somewhat controversial. Traditionally, this species has been called P. sprengerana (L.) Poir. in most of the botanical literature (Steyermark, 1963), but as noted by Lack (1974) and Greuter (2003), that name instead applies to an Old World species of Hieracium. Lack (1974) referred to the species as P. integrifolia Desf., but Holzapfel (1994) suggested that this epithet was not validly published and used the name P. altissima. Most recently, Greuter (2003), noted that the name P. rhagadioloides is the oldest valid name for the taxon, rejecting Lack’s (1974) earlier arguments against the acceptance of this name.

 
 


 

 
 
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