55. Eleocharis cancellata S. Watson, Proc. Amer. Acad. Arts. 18: 170. 1883.
Plants annual(?), densely cespitose; rhizomes obscured among culm bases, delicate, internodes very short, scales not evident. Culms mostly ascending, terete or 4-angled, 2 cm × 0.2–0.3 mm, soft. Leaves: distal leaf sheaths persistent, greenish to whitish, translucent, membranous, apex blunt. Spikelets ovoid, 2–3 × 1 mm, apex acute; floral scales 7–10, 5 per mm of rachilla, bright brown or colorless, medially greenish, ovate to lanceolate, not folded lengthwise, 0.8–1.2(–1.5) × 0.6–0.8 mm, midrib obscure to slightly keeled, apex acute to acuminate. Flowers: perianth bristles absent; anthers orange-brown, 0.2–0.3 mm. Achenes brownish, broadly ovoid to obpyriform, much less than 2 times longer than wide, with angles plus longitudinal ridges ca. 6, rather obscure, 0.5–0.55 × 0.35 mm, apex blunt, trabeculae 15–20, distinct. Tubercles grayish or brownish, often appressed, mostly pyramidal, 0.1 × 0.1 mm.
Fruiting fall (Sep). Wet springy places; of conservation concern; 1700 m; Tex.; Mexico (San Luis Potosí).
Eleocharis cancellata is very similar to E. bella. The achenes of E. cancellata are relatively broader in relation to their length, the angles and ridges obscure and fewer, and the trabeculae very distinct and faintly wavy at 35X. R. McVaugh and W. R. Anderson (1974+, vol. 13) mentioned possible intermediates with E. acicularis from Mexico. Eleocharis cancellata has been reported from the flora area from three collections: (1) Texas, Jeff Davis County, A. Brant et al. 2237, 1993, originally identified as E. bella; (2) southwestern Texas or northern Mexico (probably from near San Antonio), Parry & Palmer 912, 1879–1880; and (3) Arizona, Santa Cruz County(?), C. Wright 1937, collected in 1851. Although it was also reported from New Mexico (H. K. Svenson 1929), E. cancellata probably does not occur there (R. McVaugh and W. R. Anderson 1974+, vol. 13).