yellow starthistle
Centaurea solstitialis L.
Description from Invasive.org
- Appearance
- This annual plant can grow 0.25-3 ft. (0.07-0.9 m) in height.
- Foliage
- Leaves that are located near the base are petiolate, dissected, 2-6 in. (5-15.2 cm) long. These certain leaves are normally absent during the time of flowering. Leaves further up the stem are 0.4-4 in. (1-10 cm) long.
- Flowers
- Flowering occurs from June-October. Yellow flowers appear in heads at the tips of the branches. Bracts that extend the flower head have a small cluster of spines.
- Fruit
- This seed type represents between 10 and 25% of the total seed and often remains in the seed-heads until late fall or winter. The central flowers produce glossy, gray, or tan to mottled cream-colored and tan seeds with a short, stiff, unequal, white pappus 0.08-0.2 in. (2-5 mm) long.
- Ecological Threat
- Centaurea solstitialis invades woodlands, fields, pastures and roadsides.
Resources
- Biology and Biological Control of Yellow Starthistle - USDA Forest Service
- Weeds Gone Wild: Alien Plant Invaders of Natural Areas - Plant Conservation Alliance
- Element Stewardship Abstract - The Nature Conservancy
- Weed of the Week - USDA Forest Service
- Weed Field Guide - USDA Forest Service
Selected Images from Invasive.org
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Flower(s)
Charles Turner, USDA Agricultural Research Service, Bugwood.org
Additional Resolutions & Image Usage
Charles Turner, USDA Agricultural Research Service, Bugwood.org
Additional Resolutions & Image Usage
Plant(s) Rosette
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage
Plant(s) in flower
Charles Turner, USDA Agricultural Research Service, Bugwood.org
Additional Resolutions & Image Usage
Charles Turner, USDA Agricultural Research Service, Bugwood.org
Additional Resolutions & Image Usage