Eleocharis interstincta |
Eleocharis montana |
|
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knotted spikerush |
mountain spikerush |
|
Habit | Plants perennial; rhizomes 2–4 mm thick, firm, longer internodes 3–7.5 cm, scales 5 mm, tubers absent. | Plants perennial, densely tufted or mat-forming; rhizomes mostly hidden by culms and roots, fairly long, 3 mm thick, hard, cortex persistent, longer internodes to 3 mm, scales persistent, ca. 8 mm, membranous, slightly fibrous. |
Culms | terete, 45–100 cm × (3.2–)5–9.4 mm, soft to firm, sometimes septate-nodulose proximally, not distally, internally hollow with complete transverse septa, closer together near the spikelet, evident externally; plants never forming filiform, flaccid culms. |
terete, when dry with few to many blunt ridges, 10–70 cm × 0.5–2 mm, soft to firm, internally hollow with complete transverse septa 2–5 mm apart, usually evident externally except in narrowest culms. |
Leaves | distal leaf sheaths persistent, membranous to thinly papery, apex acute to acuminate. |
distal leaf sheaths persistent, not splitting, proximally dark red, distally green or brown, slightly callose, papery, apex obtuse, tooth present, 0.3–1 mm. |
Spikelets | not proliferous, (20–)40–62 × 4–7 mm; rachilla joints bearing prominent wing-like remnants of floral scales; proximal scale empty, amplexicaulous, (3–)3.5–5 mm; floral scales 115–220, 1–3 per mm of rachilla, stramineous to pale brown, usually with pale to dark brown submarginal band, midrib region sometimes greenish, obovate to broadly oblong, (4–)4.5–5 × 2.8–4 mm, cartilaginous, often membranous toward margins, margins broadly translucent, membranous, apex rounded to subacute. |
ovoid, 6–21 × 3–4 mm, apex acute to obtuse; proximal scale amplexicaulous, entire; subproximal scale empty or with flower; floral scales appressed in fruit, 100–500+, (15–)30–40 per mm of rachilla, medium brown to colorless, midrib regions greenish to colorless, ovate, 1.5–2.5 × 1–1.5 mm, entire, apex rounded to subacute, carinate in distal part of spikelet. |
Flowers | perianth bristles 6–8, stramineous, stout, flattened, subequal, exceeding achene, to 2.9 mm, coarsely spinulose; anthers stramineous to reddish, 2.5–5 mm; styles 2-fid or 3-fid. |
perianth bristles 6–8, pale brown, medium stout, from less than 1/2 achene length to sometimes slightly exceeding tubercle, retrorsely spinulose; stamens 1; anthers dark yellow to brown, 0.6–1 mm; styles 3-fid or some 2-fid. |
Achenes | stramineous to golden-yellow or reddish brown or gray, obovoid to obpyriform, biconvex or nearly plano-convex, often with abaxial longitudinal ridge, 1.4–1.8(–2) × 1.1–1.4 mm, markedly sculptured at 10–15X, each face with 23–37 rows of transversely elongated cells, the longitudinal walls separating the cells often prominent, apex with short neck 0.7–0.8 mm wide. |
falling with scales, dark green or medium brown, obovoid to obpyriform, biconvex or sometimes some compressedtrigonous in same spikelet, lateral angles prominent, abaxial angle absent or evident, not prominent, 0.8–1.1 × 0.7–0.8 mm, neck short or absent, finely cancellate at 10–20X, sometimes finely rugulose, with 15 horizontal ridges in vertical series. |
Tubercles | dark brown, lamelliform, slightly higher than wide, 0.7–1.1 × 0.5–0.7 mm. |
brown, pyramidal, mostly depressed, 0.2–0.35 × 0.2–0.4 mm. |
Eleocharis interstincta |
Eleocharis montana |
|
Phenology | Fruiting late spring–winter. | Fruiting winter–fall. |
Habitat | Fresh ponds, lakeshores, marshes, springs, ditches, canals | Fresh temporary or artificial ponds, ditches, burned savannas, swamp margins |
Elevation | 10–500 m (0–1600 ft) | 20–90[–2800] m (100–300[–9200] ft) |
Distribution |
FL; OK; TX; Mexico; Central America; e South America
|
AL; AZ; FL; GA; LA; TX; Mexico; Central America; South America; West Indies |
Discussion | Contrary to statements in the literature, sectioning reveals that the culm septa are closer together near the spikelet than in the rest of the culm in both Eleocharis interstincta and E. equisetoides. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The taxonomy of the septate-culmed species here treated as Eleocharis montana and E. ravenelii should be evaluated. According to H. K. Svenson (1957), the type of E. montana from near Bogotá, Colombia, is the mountain extreme of the species; it has swollen culms with no visible septation. Specimens from Acadia and St. Landry parishes, Louisiana, are intermediate between Eleocharis montana and E. montevidensis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 119. | FNA vol. 23, p. 79. |
Parent taxa | Cyperaceae > Eleocharis > subg. Limnochloa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis |
Sibling taxa | ||
Synonyms | Scirpus interstinctus | Scirpus montanus, E. montana var. nodulosa, E. nodulosa |
Name authority | (Vahl) Roemer & Schultes: in J. J. Roemer et al., Syst. Veg. 2: 149. (1817) | (Kunth) Roemer & Schultes: in J. J. Roemer et al., Syst. Veg. 2: 153. (1817) |
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