Asteraceae
Daisy Family
Cirsium discolor (Muhl. ex Willd.) Sprengel
- Stem: biennial; 4’ to 5’ tall; unbranched; hairy.
- Leaves: alternate; deeply, pinnately lobed with sharp points; 12” long by 2” wide; sessile; green with few long hairs above and white with dense hairs below.
- Inflorescence: few heads from stem tip and upper axils.
- Heads: purple disk flowers protrude above 1” fillaries which are weakly spine-tipped; heads about 1” in diameter; flowering from mid-August to mid-September.
- Fruits: “seeds” (fruits) 3/32” long; plume hairs finely branched, 3/4” long; fruiting begins in late August.
- Habitat: frequent on upland to lowland prairies, on roadsides, in pastures, and in open places; especially when disturbed.
- Notes: Bull thistle (Cirsium vulgare [Savi] Tenore), a weedy alien, is similar but has leaf edges that continue down the stem as wings and lacks the whitish underside of the leaf.
- Bibliography from Biodiversity Heritage Library
- Vascular Plants of Iowa
Can be found in these counties:
