Eleocharis cellulosa |
Eleocharis brittonii |
|
---|---|---|
Gulf Coast spikerush, Gulfcoast spikesedge |
Britton's spike-rush |
|
Habit | Plants perennial; rhizomes 1–4 mm thick, soft to hard, longer internodes 3–7.5 cm, scales 5 mm, tubers absent. | Plants usually annual, tufted, often stoloniferous; rhizomes absent. |
Culms | terete or obtusely trigonous, 30–80 cm × 1–5 mm, soft to hard, not septate-nodulose, internally spongy, transverse septa incomplete; plants never forming filiform, flaccid culms. |
ascending, quadrangular, sulcate (not sulcate in Eleocharis sp. |
Leaves | distal leaf sheaths persistent, membranous, apex acute to acuminate, often prolonged into a slender awn to 4 mm. |
distal leaf sheaths persistent or fugaceous, pale brown or green, sometimes streaked red-brown, membranous to translucent, apex acute to acuminate. |
Spikelets | not proliferous, 14–54 × 3–5.6 mm; rachilla joints without winglike remnants of floral scales; proximal scale empty, amplexicaulous, 2.5–4.9 mm; floral scales 40–180, 2–3 per mm of rachilla, stramineous to pale brown, flanks sometimes minutely dotted reddish, usually with pale to dark brown, reddish, or purplish submarginal band, obovate to suborbicular, widest in middle, 3.4–4.5(–6) × 3–4.8 mm, cartilaginous, membranous toward margins, margins broadly translucent, membranous, apex rounded. |
basal spikelets absent; often proliferous, ellipsoid to ovoid, terete, 2–10.5 × 1–2.8 mm, apex acute; proximal scale empty, persistent, amplexicaulous, dissimilar to floral scales, slightly longer, often resembling an involucral bract, elliptic or lanceolate, 1.4–2.7 × 0.8–1.2 mm, apex rounded, midrib markedly thickened and broad; subproximal scale with a flower; floral scales spiraled, 13–76, 9–13 per mm of rachilla, colorless or pale brown, streaked or mottled pale brown to red-brown, midribs sometimes green, ovate, elliptic, or obovate, 0.8–2.2 × 0.5–1 mm, papery or membranous, midrib evident to prominent, apex rounded. |
Flowers | perianth bristles 6–7, medium brown to pale brown or reddish, slender, proximally slightly flattened, subequal to unequal, mostly exceeding achene, 2–3.4 mm, smooth or sometimes finely retrorsely spinulose; anthers reddish brown, 1.7–2.5 mm; styles 3-fid. |
perianth bristles 5–6 or absent, appressed to achene, white, vestigial to shorter than achene, to 0.3 mm; spinules not evident at 45X; stamens 2–3; anthers 0.2–0.45 mm; styles 3-fid. |
Achenes | brown, biconvex, obpyriform, 2.2–2.8 × 1.3–1.9 mm, markedly sculptured at 10–15X, each face with (17–)20–24 rows of isodiametric to slightly transversely elongated cells, apex narrowed to a stout, often pale, spongy region 0.8–1.1 mm wide at base, 1/2–3/4 of achene width. |
grayish to pale olive or yellowish, often minutely brown-spotted, obovoid, trigonous, angles prominent, 0.45–0.8 × 0.3–0.55 mm, apex constricted proximal to tubercle, smooth or finely pitted at 30X. |
Tubercles | dark brown, lamelliform to pyramidal, 0.1–0.5 × 0.2–0.5 mm. |
gray, green, or yellowish, birettaform, trigonous, 0.05–0.1 × 0.15–0.3 mm. |
Aff | . |
|
Brittonii | ), 7–37 cm × 0.2–0.6 mm, soft to firm. |
|
2n | = 10. |
|
Eleocharis cellulosa |
Eleocharis brittonii |
|
Phenology | Fruiting late spring–winter. | Fruiting mid spring–winter. |
Habitat | Brackish to saline marshes, shores, ditches, mostly coastal, often abundant or dominant | Freshwater, moist terrestrial sites, peaty ponds, swamps |
Elevation | 0 (Florida)–600 (Arkansas, Texas) m (0 (Florida)–2000 (Arkansas, Texas) ft) | 0–100 m (0–300 ft) |
Distribution |
AL; AR; FL; GA; MS; NC; SC; TX; Mexico; West Indies; Central America (Nicaragua)
|
AL; AR; FL; GA; LA; MO; MS; SC; TN; TX
|
Discussion | Preliminary studies suggest that Eleocharis brittonii may be comprised of two entities that may warrant taxonomic recognition, perhaps at the species level. Typical E. brittonii is usually robust, with floral scales pale brown and papery, bristles well developed, and achenes to 0.8 mm, clearly pitted at 30X. It is known from Alabama, Florida, Georgia, Louisiana, Mississippi, New Jersey, and South Carolina. The second variant is usually small with floral scales whitish with red-brown markings, bristles absent or poorly developed, and achenes not more than 0.6 mm, smooth at 30X. We have annotated specimens of this second variant E. sp. aff. brittonii, known from Arkansas, Florida, Georgia, Louisiana, Mississippi, Tennessee, and Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 23, p. 118. | FNA vol. 23. |
Parent taxa | Cyperaceae > Eleocharis > subg. Limnochloa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae |
Sibling taxa | ||
Synonyms | E. microcarpa var. brittonii | |
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York 3: 298. (1836) | Svenson ex Small: Man. S.E. Fl., 164. (1933) |
Web links |