Plants 0.7--2.8 m in flower. Leaves pungent; blade 21--98 ´ 2--6 cm. Inflorescences 2--3-pinnately compound, scaly; proximal primary bracts often inconspicuous, shorter than lateral branches; lateral branches laxly or densely flowered, appearing capitate or cylindric, 0.5--40 cm. Staminate flowers sessile, scaly; floral bracts 2.5--3.5(--5.5) mm, exceeded by sepals; sepals ovate, 2.5--4 mm; petals 3.5--4.5 mm. Pistillate flowers sessile, scaly; floral bracts 3.5--4.5(--6) mm, exceeded by sepals; sepals ovate, 3--4 mm; petals ovate, 4.5--5 mm; ovary almost wholly superior. Capsules 6--8.5 mm, scaly, glabrescent with age.

Flowering spring--summer. In gravel and on sandstone formations; 0--150 m; Tex.; Mexico; Central America.