Plants tufted, without creeping rhizomes. Culms to 45 cm × 0.2-1 mm. Leaves: distal leaf sheaths persistent, firm, distally tightly sheathing, apex acute. Spikelets orbicular to ovoid, 1-9 × 1-4 mm, apex rounded to acute; proximal scale without flower, not amplexicaulous; floral scales to 125, 11-14 per mm of rachilla, tightly appressed, dark red-brown to stramineous, ovate to elliptic, 0.8-3 × 0.6-2(-2.3) mm, membranous to cartilaginous, apex rounded to acute. Flowers: perianth bristles (0-)4-8, typically 7, red-brown, rarely whitish, vestigial to much exceeding tubercle, typically equaling achene, spinules few to dense; styles 2-fid. Achenes brown ripening to black, biconvex, orbicular to obpyriform, 0.5-1.1 × 0.3-0.7 mm, apex rarely constricted proximal to tubercle, very finely reticulate at 40X. Tubercles stramineous to whitish, umbonate to subconic, 0.2-0.4 × 0.2-0.5 mm, apex rounded to acute. 2n = 10.
The name Eleocharis caribaea (Rottbøll) S. F. Blake is considered by most contemporary authorities to be misapplied (K. L. Wilson 1990). Eleocharis geniculata has been reported from South Carolina; I have not seen a voucher.
Annual herb, tufted 3 cm - 45 cm tall Leaves: reduced to bladeless sheaths, basal, two per culm, margins fused and enclosing culm, pointed at the apex, and firm. Flowers: minute, spirally arranged on the axis of the spikelet, lacking sepals and petals, with zero to eight (usually seven) bristles, subtended by a scale. Bristles (when present) reddish brown, equal to or longer than achene. Stamens usually three, exserted. Anthers about 0.5 mm long. Pistil one. Style two-cleft. Fruit: a one-seeded achene, brown becoming black, 0.5 - 1 mm long, about 0.5 mm wide, spherical to reverse pear-shaped, lenticular (lens-shaped), finely wrinkled (at 40X). Tubercle straw-colored to whitish, to about 0.5 mm long and wide, with a rounded to pointed apex. Seed with a thin, non-adherent wall. Spikelets: solitary, 1 - 9 mm long, 1 - 4 mm wide, spherical to egg-shaped with a rounded to pointed apex, with up to 125 floral scales. Scales spirally arranged and overlapping, tightly appressed, straw-colored to dark reddish brown, 0.8 - 3 mm long, 0.6 - 2 mm wide, egg-shaped to elliptical with a rounded to pointed apex, membranous to cartilage-like. Culms: upright to widely spreading, unbranched, 3 cm - 45 cm long, to 1 mm wide, nearly circular in cross-section, enclosed basally by two fused sheaths.
Similar species: No information at this time.
Flowering: late July to late September
Habitat and ecology: Rare in the Chicago Region, and currently known only from Lake and Porter counties in Indiana. Found on calcareous marsh borders.
Occurence in the Chicago region: native
Etymology: i>Eleocharis comes from the Greek words heleios, meaning "dwelling in a marsh," and charis, meaning grace. Geniculata means "sharply bent."
Author: The Morton Arboretum
Common Name: Canada spikesedge Duration: Annual Nativity: Native Lifeform: Graminoid General: Tufted annual without rhizomes, stems to 45 cm, each 0.2-1 mm thick. Vegetative: Leaves with persistent sheaths above, firm, tightly sheathed at top with an acute apex. Inflorescence: Spikelets orbicular to ovoid, 1-9 mm by 1-4 mm, rounded to acute apex; upper scale without flower, not stem clasping, up to 125 floral scales, 11-14 per mm of rachilla, tightly appressed, dark red-brown to stramineous, ovate to elliptic, 1-3 mm by 0.5-2 mm, membranous, with rounded to acute apex; flowers with 4-8 perianth bristles, red-brown, rarely whitish, typically equaling achene, small spines few to dense, styles bifid; achenes brown ripening to black, biconvex, orbicular to obpyriform, 0.5-1 mm by 1 mm, finely reticulate under magnification. Ecology: Found along creeks, slack water, in depressions, along salt marshes, lagoons, and ditches from sea level to 5,000 ft (1524 m); flowers in April-November. Notes: As with most of these species, you need to get a collection to adequately assess its identity. The terminal spikes tend to be more ovoid than others in the genus. Ethnobotany: Unknown Etymology: Eleocharis is from Greek heleos or helos, a marsh, low ground, meadow and charis, grace, beauty, hence marsh grace, while geniculata means jointed or bent like a knee at a node. Synonyms: Eleocharis caribaea, E. capitata var. dispar, E. caribaea var. dispar, Scirpus caribaea Editor: SBuckley, 2010
Tufted annual; stems erect or divaricate, 3-20 cm, rarely more; sheaths firm, very oblique at the top; spikelet ovoid, 2-6 mm; scales numerous, round- ovate, obtuse; bristles brown, usually exceeding the achene, seldom shorter; anthers ca 0.5 mm; achene lenticular, black, shining, obovoid, 0.7-1 mm; tubercle pale, minute, very short. Pantropical, n. to S.C. and irregularly to Ont., Mich., and Ind. (E. capitata; E. geniculata, misapplied)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
In wet, marl borders of lakes and in dried-up sloughs. In addition to the counties shown on the map, it is known in the Great Lakes area only from Washtenaw County, in southeastern Michigan and from southern Ontario.