135. Euphorbia eriantha Bentham, Bot. Voy. Sulphur. 51. 1844.
Beetle spurge Beetle spurge
Herbs, annual or perennial, with slender to thick, woody taproot. Stems erect to ascending, 10–75 cm, glabrous or with scattered appressed hairs (especially near nodes); branches arcuate. Leaves alternate; petiole 0.1–0.4 mm, often indistinct, glabrous or sparsely pilose to shortly sericeous; blade linear to linear-elliptic, 20–55 × 1–3 mm, base attenuate, margins entire or with 2–4 inconspicuous teeth near apex, apex acute, abaxial surface pilose to shortly sericeous, adaxial surface usually glabrous, rarely pilose to shortly sericeous; only midvein conspicuous. Cyathial arrangement: terminal cymose branches 1, 1–2-branched; pleiochasial bracts 2–3, opposite or whorled, wholly green, similar in shape and size to distal leaves; dichasial bracts similar in shape to distal leaves or often highly reduced. Cyathia: peduncle 1–1.9 mm. Involucre obconic, 2.1–2.6 × 1.3–2 mm, canescent; involucral lobes triangular, obscured by hairs; glands (2–)4–5, green to maroon, color often obscured by hairs, sessile and broadly attached, 0.5–0.6 × 0.5–0.6 mm, opening oblong to nearly circular, densely canescent; appendages petaloid, whitish, hoodlike, incurved and covering glands, 0.5–1 × 0.5–0.8 mm, divided into 5–12 fringed, subulate segments, densely canescent. Staminate flowers 20–25. Pistillate flowers: ovary canescent; styles 0.9–1.5 mm, unbranched. Capsules oblong to ovoid, 4.4–4.9 × 3.5–4.1 mm, canescent (often with interspersed glabrescent patches); columella 3.5–3.9 mm. Seeds mottled black and gray or light brown, oblong or slightly ovoid, dorsiventrally compressed in cross section, 2.8–4.1 × 2–2.4 mm, irregularly pitted and tuberculate; caruncle 0.4–0.8 × 0.6–1.1 mm.
Flowering and fruiting year-round in response to sufficient rainfall. Desert scrub on rocky slopes and along washes; 60–800 m; Ariz., Calif., N.Mex., Tex.; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, San Luis Potosí, Sonora).