Eleocharis obtusa (Willd.) Schult.

Eleocharis obtusa (Wilid.) Schultes in R. & S Syst. Veg. Mant. 2 : 89. 1824.
Scirpus obtusus Willd. Enum. 76. 1809. (Pennsylvania.)
Scirpus elegantuhis Steud. Syn. Cvp. 317. 1855. (New Orleans.)
Eleocharis diandra C. Wright, Bull. Torrey Club 10: 101. 1883. (Connecticut.)
Eleocharis obtusa var. jejuna Fernald, Proc. Am. Acad. 34: 492. 1899. (Maine.)
Eleocharis ovata var. gigantea Clarke; Britten, Jour. N. Y. Micr. Soc. 5: 103. 1889. Nomen
nudum. (Oregon.) Eleocharis obtusa var. gigantea Fernald, Proc. Am. Acad. 34: 493. 1899. Eleocharis Macounii Fernald, Proc. Am. Acad. 34 : 497. 1899. (Quebec.) Heleocharis ovata var. obtusa Kiikenth. ; Skottsb. Acta Hort. Gothob. 2: 212. 1926. Eleocharis obtusa var. Peasei Svenson, Rhodora 31 : 217. 1929. (New Hampshire.) Eleocharis obtusa var. ellipsoidalis Fernald; Svenson, Rhodora 31: 218. 1929. (Massachusetts.)
Annual (rarely perennial, as in var. ellipsoidalis), usually erect; culms numerous, 0.3-5 dm. long, yellowish-green, capillary to l.S mm. in diameter ; sheaths purplish at base, at the apex firm and somewhat oblique ; spikelets globose-ovoid to ovoid-cylindric, obtuse, manyflowered, 2-13 mm. long, closely or loosely flowered ; scales ovate-oblong to suborbicular, brown, with a narrow scarious margin and usually a greenish midrib; style bifid or trifid; achene 1-1.5 mm. long, turbinate-obovoid, narrowed at the base, pale to deep brown, smooth and shining; style-base strongly flattened, deltoid, acute, nearly as wide as the achene; bristles 6 or 7, dark brown, coarse, exceeding the achene, retrorsely toothed.
Type locality : Pennsylvania.
Distribution: Nova Scotia, west to Minnesota, south to northern Florida and Texas : Colorado and New Mexico ; British Columbia and Idaho to northern California ; Hawaiian Islands.