Machaonia pringlei A. Gray

Machaonia pringlei A. Gray, Proc. Am. Acad. 21: 380. 1886 A shrub 1-2 meters high, unarmed, the branches reddish-brown, very sparsely lenticellate, the branchlets glabrous, the internodes short or elongate; stipules 3 mm. long, deltoid-acuminate, glandular-dentate; leaves opposite, short-petiolate, the petioles marginate to the base, the blades linear-lanceolate, 3-6 cm. long, 4-8 mm. wide, long-attenuate to each end, chartaceous, glabrous, the costa stout and very prominent beneath, the lateral nerves mostly obsolete, the margin often obscurely crispate; inflorescence many-flow r ered, 3-6.5 cm. broad, the branches sparsely puberulent, the flowers partly sessile and partly pedicellate, the bracts linear, often elongate and foliaceous; hypanthium turbinate, densely covered with short white subappressed hairs, the 4 or 5 calyx-lobes broadly cuneate, usually truncate at the apex, green, glabrous, nearly as long as the hypanthium; corolla 4 mm. long, glabrous outside, the lobes oval-obovate, longer than the tube, the margins undulate; anthers exserted.
Type locality: Limestone ledges of the mountains near Jimulco, Coahuila. Distribution: Known only from the type locality.