[Hemicarpha micrantha (Vahl) Pax, moreHemicarpha micrantha var. minor (Schrad.) Friedland, Isolepis caespitula , Lipocarpha micrantha (Vahl) G. C. Tucker, Scirpus micranthus Vahl, Scirpus micranthus var. micranthus , Scirpus micranthus var. minor (Schrad. ex Roemer & J.A. Schultes) Boivin]
Culms 2-20 cm × 0.3-0.5 mm. Leaves 1.5-10 cm × 0.3-0.5 mm. Inflorescences: spikes 1-2(-3), ovoid (to globose), 1-3(-5) × 1-2 mm, not bristly; bracts 1-2(-3), longest erect, others spreading, 2-5 cm × 0.3-0.6 mm. Spikelets: floral scales 2; 1st scale laterally yellowish to reddish brown, with green midvein, obtrullate to obovate, widest at or distal to mid length, 0.5-1 × 0.3-0.4 mm; 2d scale 2-fid, sometimes absent, 0.1-0.2 × 0.1 mm; 3d scale absent; stamen 1; anther 0.1-0.2 mm; stigmas 2. Achenes obovoid to broadly ellipsoid, 0.4-0.6(-0.7) × 0.2-0.3 mm, 1.5-2.5 times long as wide.
Annual herb, tufted 2 - 20 cm tall Leaves: basal, 1.5 - 10 cm long, to about 0.5 mm wide, linear, parallel-veined, with a sheathing base that encloses the stem. Inflorescence: a terminal, egg-shaped cluster of one to two spikes, 1 - 3 mm long, 1 - 2 mm wide, subtended by leaf-like bracts. Bracts one to two, longest upright, others spreading, 2 - 5 cm long, about 0.5 mm wide. Spikes composed of numerous spikelets. Flowers: minute, subtended by a floral scale, lacking sepals and petals, with one or two scales. Stamen one, exserted. Pistil one. Style linear, two- to three-cleft. Fruit: a one-seeded achene, about 0.5 mm long and 0.3 mm wide, 1.5 to 2.5 times as long as wide, reverse egg-shaped to widely ellipsoid. Seed with a thin, non-adherent wall. Culm: 2 - 20 cm long, to 0.5 mm wide, circular in cross-section, solid. Spikelets: bearing two floral scales. First scale greenish down the middle, yellowish to reddish brown along the sides, 0.5 - 1 mm long, under 0.5 mm wide, more or less diamond-shaped to reverse egg-shaped (but widest at or above the middle). Second scale sometimes absent, to 0.2 mm long and 0.1 mm wide, two-cleft.
Similar species: No information at this time.
Flowering: late June to early October
Habitat and ecology: Local on wet sandy shores of ponds and streams.
Occurence in the Chicago region: native
Etymology: Lipocarpha comes from the Greek words lipos, meaning fat, and carphos, meaning chaff, referring to the inner scale thickness of some species.
Author: The Morton Arboretum
Cronquist et al. 1977, FNA 2002, Kearney and Peebles 1969
Common Name: smallflower halfchaff sedge Duration: Annual Nativity: Native Lifeform: Graminoid General: Delicate tufted annual with clustered terete stems 2-20 cm tall. Vegetative: Blades 1.5-10 cm long narrow, scarcely 0.5 mm wide, appearing like slender stems. Inflorescence: Several spikes at the summit of stem, usually 1-3 per stem, sessile, ovoid, 2-6 mm long and 1.5-2.5 mm thick, floral scales 2, firm, widest at or above midlength abruptly contracted to a blunt mucro; inner scale inconspicuous, 0.1-0.2 mm, hyaline, bifid, outer larger, equaling or slightly exceeding achenes; achenes obovoid to broadly ellipsoid, minute, 0.5 mm long. Ecology: Found on wet sandy soils, especially on sand bars and stream banks from 2,500-4,000 ft (610-1219 m); flowers June-September. Notes: Distinguished by the inner scale being 0.1-0.2 mm or absent. Also can be distinguished by the very delicate narrow leaf blades. Ethnobotany: Unknown Etymology: Lipocarpha comes from Greek leipo, meaning to be deficient or wanting, and karphos for chip of straw, micrantha means small flowered. Synonyms: Hemicarpha micrantha, Hemicarpha micrantha var. minor, Scirpus micranthus, Scirpus micranthus var. minor Editor: SBuckley, 2010
Tufted annual, 2-10(-20) cm; lvs to 10 cm נ0.5 mm, resembling the stems; spikes mostly 1-3 per stem, ovoid, 2-6 mm; scales numerous, 1-2 mm, firm, obovate, mucronate or (especially the lower) with a short awn-tip; achene 0.5-0.7 mm. Moist sandy soil; trop. Amer., n. to Me., Minn., and Wash. Most of our plants (as well as the tropical ones) belong to the var. micrantha, with the inner scale ±strongly reduced (sometimes bifid) or obsolete. Var. aristulata Coville (H. drummondii), with a relatively well developed inner scale ±equaling the achene, occurs chiefly in w. U.S., extending e. sporadically to Ohio.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.