Small Spike Rush

Eleocharis minima is most often confused with E. bicolor and E. baldwinii (see comments under 33. E. bicolor). Although floral scales in E. minima often superficially appear to be spirally disposed, in reality they are spirodistichous, ± decussate, while in E. baldwinii they are strictly distichous in one plane. The number of floral scales per millimeter is much greater in E. minima than in E. baldwinii.

Plants annual, tufted, often mat-forming, often stoloniferous, sometimes entirely vegetative; rhizomes absent. Culms erect, ascending or arching, quadrangular, sulcate, 1–13 cm × 0.1–0.3 mm, soft. Leaves: distal leaf sheaths persistent or disintegrating, red-brown, stramineous, green, or mottled red-brown, translucent, apex narrowly acute. Spikelets: basal spikelets often present, bisexual; often proliferous, ovoid or ellipsoid, laterally compressed when young, but terete at maturity, 2–7 × 1–2.6 mm, acute; proximal scale empty, often persistent, amplexicaulous, similar to floral scales; subproximal scale with a flower; floral scales spirodistichous (superficially appearing ± spiraled), (4–)10–28, 6–9 per mm of rachilla, pale brown, mottled red-brown to purple, ovate or elliptic, 1.3–2.1 × 0.7–1 mm, membranous, midribs green and red-brown, prominent, apex rounded to obtuse. Flowers: perianth bristles 6, colorless, white, or stramineous, slightly shorter than to equaling achene, spinules retrorse, acute; stamens 3; anthers 0.4–0.5 mm; styles 3-fid. Achenes greenish or pale brown or red-brown, often clearly spotted greenish or red-brown, ellipsoid to obovoid, trigonous (or terete?), angles prominent (keeled), 0.6–0.8 × 0.4–0.5 mm, apex constricted proximal to tubercle, smooth. Tubercles red-brown, pyramidal, trigonous, 0.1–0.3 × 0.2–0.4 mm.

Fla., Md., Tex.; Mexico; West Indies; Central America (Costa Rica, El Salvador, Guatemala, Nicaragua, Panama); South America.

Fruiting mid spring–fall.

Freshwater, sandy and peaty shores of lakes, muddy areas; 0–400m.

Chaetocyperus jamesonii Steudel; C. polymorphus Lindley & Nees; C. viviparus Nees; Eleocharis durandii Boeckeler; E. jamesonii (Steudel) N. E. Brown; E. minima var. ambigua Kükenthal; E. oropuchensis Britton; E. savannarum Britton; E. subtilis Boeckeler; E. tenuissima Boeckeler; E. villaricensis Maury; E. wrightiana Boeckeler; Isolepis ambigua Steudel

Eleocharis minima Kunth, Enum. PI. 2: 139. 1837
Chaetocypenis viviparus Nees in Mart. Fl. Bras. 2': 93. 1842. (Brazil.) Not Eleocharis vivi-
para Link, 1827. Chaetocypenis polymorphus Lindl. & Nees; Nees in Mart. Fl. Bras. 2^: 94. 1842, in large part.
(Brazil?) _ , ^
Chaetocypenis Jamesoni Steud. Syn. Cyp. 74. 1855. (Ecuador.) Isolepis ambigua Steud. Syn. Cyp. 91. 1855. (Brazil.) Eleocharis bicolor Chapm. Fl. S. U. S. 517. 1860. (Florida.) Heleocharis tenuissima Bock. Linnaea 36: 419. 1870. Heleocharis subtilis Bock. Linnaea 36: 426. 1870. (Brazil.)
Heleocharis Wrightiana Bock. Beitr. Cyp. 1 : 12. 1888. (Cuba.) ,, ^ . , ,,
Eleocharis villaricensis Maury; M. Micheli, Mem. Soc. Phys. Hist. Nat. Geneve 31(1)^: 138.
1889. (Paraguay.) ^ ^. ^
Heleocharis Durandii Bock. Allg. Bot. Zeitschr. 2: 34. 1896. (Costa Rica.) Eleocharis Jamesonii N. E. Brown, Kew Bull. 1921 : 356. 1921. Eleocharis savannariim Britton, Bull. Torrey Club 48: 327. 1922. (Trinidad.) Eleocharis oropiichensis Britton, Bull. Torrey Club 48: 327. 1922. (Trinidad.) Heleocharis minima var. /3 ambigua Kiikenth. Repert. Sp. Nov. 23: 194. 1926. Eleocharis uncialis Chapm.; Small, Man. SE. Fl. 163. 1933. (Florida.) Eleocharis minima var. bicolor Svenson, Rhodora 39: 219. 1937.
Dwarf, 3-7 cm. tall, cespitose, with numerous whitish, elongated fibrous roots ; culms capillary, often recurving, quadrangular-sulcate, light green, punctate; sheaths conspicuous, light or dark brown, the apex inflated, blunt, hyaline ; spikelets 2-4 mm. long, ovate, fewto many-flowered; scales ovate-lanceolate, mostly acute, dark brown with greenish midrib and hyaline margin; style trifid; achene ovate, 0.75-1.0 mm. long, sharply triangular (biconvex in var. bicolor) with convex faces, whitish to pale or olivaceous-brown, lightly reticulate to minutely striate, narrowed at the apex and base, capped by a brownish or gray, shortpyramidal, obtuse style-base; bristles inconspicuous, transparent-white, obscurely toothed, shorter than the achene, often greatly reduced.
Type locality : Brazil.
Distribution: Florida, Georgia, Texas, California; Mexico; Costa Rica; San Salvador; Cuba ; Jamaica ; tropical South America.