Rattlesnake-master

Eryngium yuccifolium, commonly known as rattlesnake master, button eryngo or button snakeroot, is a striking herbaceous perennial of the family Apiaceae, native to the prairies, savannas, glades and open woodlands of the eastern and central United States. The plant grows 0.6–1.5 m tall from a thick, woody, fibrous taproot and produces stout, ribbed, glaucous bluish-green stems that are little-branched below the inflorescence. The basal leaves are strongly yucca-like (hence the specific epithet): linear, parallel-veined, stiff, leathery, 30–90 cm long and 1.5–3 cm wide, with widely spaced bristle-like teeth along the margins. Stem leaves are similar but progressively smaller. The inflorescence is highly atypical for the family, consisting of dense, ovoid to globose, button-like heads 1.5–2.5 cm across, each composed of numerous tiny, greenish-white flowers subtended by stiff, awl-shaped bracts. The heads are arranged in a corymb-like cyme at the stem apex. Flowering occurs from June to September. The fruit is a small, scaly schizocarp.