Eryngium madrense S. Wats.

Eryngium madrense S. Wats. Proc. Am. Acad. 23: 274. 1888
Slender, caulescent, glabrous perennials (?), 5-6 dm. high, from a fascicle of fleshy-fibrous roots, the stems solitary, strictly erect, branching; basal leaves lanceolate, 1-2 dm. long, 1-2 cm. broad, acuminate, ternate or pinnatisect, the linear or lanceolate lobes entire or obsoletely serrate, 1-2 cm. long, the venation pinnately reticulate; petioles fistulose, septate, sheathing at the base, 1 .5-3 dm. long, exceeding the blades; cauline leaves like the basal, ternately parted with rigid, bipinnatisect, linear divisions, 1-2 cm. long, the upper leaves opposite and sessile; inflorescence successively trifurcate or cymose, the heads rather large, short-pedunculate, the flowers numerous; heads blue, broadly cylindrie, 10-12 mm. long, 6-8 mm. broad; bracts 8-10, rigid, spreading, linear to lanceolate, 12-18 mm. long, pungent, acute, entire or with an occasional spinose tooth, green beneath and yellowish-white above, exceeding the heads; bractlets subulate, 2-3 mm. long, rigid, entire, slightly dilated at the base, exceeding the fruit; coma of a single, rigid, deeply parted bractlet, 15-18 mm. long; sepals lanceolate, 0.5 mm. long, obtuse, apiculate; petals obovate, about 1 mm. long; styles slender, exceeding the sepals; fruit ovoid, 1-1.5 mm. long, densely covered with lanceolate, white, subequal scales.
Type locality: In ponds on the plains at the base of the Sierra Madre, Chihuahua, Pringle 1531.
Distribution: Chihuahua (Pringle 2009).