Cirsium horridulum Michx. var. megacanthum (Nutt.) D.J. Keil

Big Spine Thistle

Herb

Biennial

Vascular

Big Spine Thistle is a native herbaceous biennial in the Sunflower family (Asteraceae). It found in near-coastal areas of Alabama. Big Spine Thistle grows in wet, open areas such as marshes, roadside ditches, bogs, and seeps. It is a biennial with a stout taproot. Fleshy lateral roots often give rise to new plants. During the first year of growth the plant forms a basal rosette of leaves. During the second spring, an erect flowering stalk 3-8 feet in height emerges. The stem is hollow, usually unbranched, glabrous to sparsely pubescent, with alternate leaves. Stem leaves are sessile to auriculate clasping, linear to elliptic in outline, subglabrous, with spiny dentate margins. The spines are up to 1 inch in length. Basal leaves are similar but larger and with spiny winged petioles. Leaves are 5-18 inches in length. Flowers are produced in heads. The heads are solitary or in corymbs. Each head is subtended by an involucre-like ring of glabrous, spiny-margined bracts. Corollas are white to pale pink or lavender in color. The fruit is an achene with a crown of plumose bristles. Botanist Thomas Nuttall described this species as "one of the most terribly armed plants in the genus."—A. Diamond

**

Native G5 (Global Rank)

**