Stems leafless, or with 1-3 leaves towards base, 10-80 cm, variously glandular-hairy or only glandular below inflorescence, glands uniformly 4-6 times longer than wide. Leaf blades to 50 cm × 8 mm. Inflorescences forming globose or cylindric-ovoid, spikelike heads, 3-45-flowered, sometimes interrupted or open, 1-8 cm, glandular-pubescent; bracts subtending pedicel in cluster; bracteoles shallowly and symmetrically 3-lobed to cleft from proximal 1/3 to base, lobes rounded to acute, often markedly unequal. Flowers usually borne in clusters of 3, proximal sometimes remote; perianth white or yellowish; tepals 3-7 mm, inner series somewhat longer and narrower; stamens 3-6 mm; ovary ellipsoid, tapering gradually to style base; styles distinct, 0.6-3 mm; pedicel 1-12 mm. Capsules ovoid to broadly ellipsoid, 4-9 mm, clearly longer than tepals and not enclosed by them, chartaceous, easily ruptured. Seeds reddish brown, ca. 1 mm; appendages 1 or 2 with one at each end, rarely absent; coat white, inflated, reticulate.

The subspecies of Triantha occidentalis recognized here are for the most part readily distinguishable from one another. Only in the area of southwest Oregon where subsp. occidentalis and subsp. brevistyla make contact might it be said that some intergradation occurs, as was previously observed by C. L. Hitchcock (1944). It should also be noted that some specimens of subsp. occidentalis from Del Norte County in northern California and the adjacent Josephine County in Oregon are not entirely typical, being very robust with large, more elongate inflorescences.