USGS - science for a changing world

Northern Prairie Wildlife Research Center

  Home About NPWRC Our Science Staff Employment Contacts Common Questions About the Site

Aquatic and Wetland Vascular Plants of the Northern Great Plains

49. Asteraceae, the Aster Family

14. Senecio L. -- Ragwort

1. Senecio congestus (R.Br.) DC. -- Swamp ragwort

Fibrous-rooted annual or biennial 1.5-10 dm tall; stems hollow, especially toward the base, sparsely to densely villous. Leaves basically all similar in shape, oblong-linear to oblong-lanceolate or the lower ones often spatulate, 4-20 cm long, 0.5-6 cm wide, or the basal leaves occasionally larger, glabrous or villous in patches, blunt to rounded at the apex, entire to coarsely toothed or sinuate-toothed, sometimes crisped, the basal and lower leaves usually petiolate, often deciduous, the middle and upper cauline leaves sessile, with winged to auriculate-clasping bases. Heads several to many, in one or more congested clusters, 1-1.5 cm across; involucre 4-8 mm high, the bracts pale and scarious toward the tip, darker at the base; rays pale yellow, 4-9 mm long. Achenes 1.5-2.5 mm long, glabrous; pappus bristles very fine and numerous, strongly accrescent. Late May--early Aug. Shores and mud flats; frequent across n ND and w MN, less common s to se SD; (Circumpolar, s in Am. to Que., n IA, e SD and Alta.).

Senecio hydrophilus Nutt. rarely occurs in the w part of our region, with records from Pennington Co., SD and Albany Co., WY. The plant is hollow-stemmed like S. congestus, but is a glaucous perennial with glabrous stems and leaves and with the cauline leaves greatly reduced upward on the stem. S. hydrophilus favors marshy, alkaline sites and can tolerate standing water.

GIF- Species Photo/Drawing
GIF- Distribution Map

Map key

Previous Section -- Petasites sagittatus (Pursh) A. Gray
Return to Family -- Asteraceae - The Aster Family
Next Section -- Senecio pseudaureus Rydb.

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Webmaster
Page Last Modified: Saturday, 02-Feb-2013 06:46:58 EST
Sioux Falls, SD [sdww54]