David J. Bogler in Flora of North America (vol. 26)
Plants perennial, polycarpic; roots spreading, 2-8 mm diam. Stems short or elongate, often with erect or reclining trunk. Leaves persistent, numerous, forming rosettes, spreading; blade long-linear, fibrous, glabrous, sometimes waxy-glaucous, bases expanded, overlapping, spoon-shaped, margins with sharp, curved prickles, apex fibrous. Inflorescences paniculate, racemose, bracteate; panicles narrow, borne on long, woody stalks; bracts leaflike proximally, stramineous distally, lanceolate; fascicles of dense racemes in axils of bracts. Flowers small, functionally unisexual, some plants with only male flowers, others with only female flowers; floral bracts laciniate, membranous; tepals 6, distinct, whitish, greenish, or purple, obovate, margins denticulate; stamens 6, rudimentary in pistillate flowers; ovary superior, 3-angled, abortive in staminate flowers; style short, ± strap-shaped, slightly expanded at tip; stigma 3-lobed, lobes weakly connate into tube; pedicel of pistillate flowers articulate. Fruits capsular, 1-locular, dry, indehiscent, 3-winged. Seed 1, golden brown, 3-angled, turbinate. x = 19.
Species within checklist:
Sonoran Desert Field Botany (ASU) Spring 2020