Northern Prairie Wildlife Research Center


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Western Wetland Flora

Field Office Guide to Plant Species

Arrow-leaf Groundsel
Senecio triangularis Hook.

JPG -- Species Photo JPG -- Distribution Map

Family: Composite (Compositae)
Flowering: July-September
Field Marks: This Senecio is readily distinguished from all others by its triangular leaves that are conspicuously toothed.
Habitat: Along streams, in wet meadows, particularly in the higher mountains.
Habit: Perennial from a thickened rootstock and with fibrous roots.
Stems: Upright, usually unbranched, up to 4 feet tall, smooth or less commonly with soft hairs, usually several growing from the base of the plant.
Leaves: Alternate, simple, distinctly triangular, pointed at the tip, heart-shaped or truncate to the base, conspicuously toothed, smooth or rarely with soft hairs, up to 8 inches long, usually much smaller, up to 5 inches wide, the lower on lon
Flowers: Many crowded together into heads, with several heads arranged to form a flat topped cluster, each head 1-1 1/4 inches across, subtended by 9-13 black-tipped bracts, all flowers with rays.
Rays: Yellow, up to 12 per head, up to 1/2 inch long or a little longer.
Sepals: 0.
Petals: 5, united to form a strap-shaped ray.
Stamens: 5.
Pistils: Ovary inferior.
Fruits: Achenes crowded into small heads, each achene smooth, several-veined, up to 1/5 inch long, bearing several soft, white bristles.

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U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/plants/florawe/species/8/senetria.htm
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Page Last Modified: Saturday, 02-Feb-2013 06:28:37 EST
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