Eastern Forest Threat Center - Spiny Plumeless Thistle

Spiny plumeless thistle is a biennial forb in the aster family growing 1-4 ft. in height. It has a single stout fleshy taproot. Stems are freely branched with spiny wings extending to flowering heads. Leaves are simple, alternate, deeply divided with alternate lobes that end in a spine, and have hairs on the underside. Flowers are pinkish-red to purple, erect, ½-1 in. in diameter, single or clustered, and have spiny wings at the base. Flowers occur at the ends of the branches and bloom from July to October in the second year. The fruit is a 4-angled dry seed. Each plant is capable of producing up to 100,000 wind-dispersed seeds that can remain viable for 10 years in the soil. Spiny plumeless thistle is found in disturbed sites, roadsides, old pastures, waste places, ditch banks, old fields, hay fields, and stream valleys. It prefers fertile soils developed over limestone, but it is adaptable and can grow in shallow soil, emerging from stone quarries. It can become weedy and form dense colonies. The presence of non-native thistles can lead to severe degradation of native grasslands and meadows. Grazing animals focus on native vegetation, giving thistles a competitive advantage.

Visit Web Source for this description...