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Yellow Starthistle (Centaurea solstitialis L.) Sunflower family - Asteraceae Photo by Tom Whitson, Roy Reichenbach |
Growth Habit: Annual, erect, rigid brancing stems. Leaves: Basal leaves deeply lobed, upper leaves not lobed, small, sharply pointed. Stem: Rigid, covered with a cottony fiber, to 30" tall, winged structures. Flower: Yellow, terminal, flower bracts are tipped with straw-colored, 3/4 inch thorn. Roots: Taproot. Seeds: Smooth, light-colored, often darker mottled, 1/8 inch long, notched just above base. Reproduction: Seeds. Habitat: Rangelands, pastures, vineyards, abandoned croplands, alfalfa and small grain fields and roadsides. Biological Controls: Seed head fly (Terellia uncinata). Herbicides: None used in Yellowstone County at this time. |
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