Isolepis funckii Steudel, Syn. Pl. Glumac. 2: 91. 1855; Bulbostylis tenuispicata (Boeckeler) Barros; Scirpus heterocarpus S. Watson; Stenophyllus funckii (Steudel) Britton

Herbs, annual, densely cespitose, scapose, delicate, low. Culms 5–10(–15) cm. Leaves 1/2 as long as to slightly exceeding scapes; sheaths stramineous to reddish, dilated, strongly ribbed; blades filiform, 0.5 mm wide, flat or involute, glabrous, margins distantly scabrid. Inflorescences: spikelets of 2 sorts, one sterile, 1(–2) atop filiform scapes or short-stalked to sessile at plant base, red-brown with green midribs, lanceoloid to lance-cylindric, 5–7 mm; the other fertile, the florets developing in sheath axils at culm base; leafy involucral bracts 1, appearing as extension of culm, or absent. Spikelets: scales of sterile spikelets lanciform, keeled, midrib excurrent at mucro; fertile scales saccate, strongly ribbed, distended by achenes. Flowers: stamens 2; anthers narrowly oblong, 0.5 mm. Achenes pale, lustrous, broadly trigonous-obovoid to subglobose, the fertile 1.5 mm, the sterile 1 mm, faces slightly convex, rugulose, papillose; tubercle a small depressed or conic button. 2n = 20.

Fruiting all year. Sandy disturbed sites such as roadbanks, fields, meadows, town lots, and pastures, sometimes weedy in open sandy land; 0–3000 m; Ariz., N.Mex.; Mexico; Central America; South America.

Bulbostylis funckii is the only heterocarpous species in Bulbostylis, the achenes of proximal spikelets being nearly twice as large and more tumid than those of aerial spikelets.