is recognizable even when not in bloom owing to its prominent, red-spined leaves and bracts. This species has only a limited distribution, along the west edge of the Mojave Desert in California. Plants have generally prostrate stems, red in color, forming low mats up to 30 inches across. Leaves are generally tomentose hairy underneath, glabrous on top, and they taper smoothly to the terminal spine. The subtending bracts occur in whorls of three; they are similar in appearance to the leaves, though shorter.
Flowers are small and inconspicuous, less than 0.2 inches in diameter; they have a ribbed, toothed involucre and a white corolla that opens to six lobes; the three outer lobes are much wider and longer than the inner three. At the center are nine stamens, fused to the base of the corolla tube, and slightly exserted. The anthers are yellow.