Isolepis cernua |
Isolepis pseudosetacea |
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fiberoptic grass, low bulrush, low clubrush, low lateral clubrush, tuft clubrush |
Gulf Coast bulrush |
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Habit | Plants annual (or perennial?); rhizomes usually obscured by culm bases and very short, sometimes vertical and elongated. | Plants annual; rhizomes absent. |
Culms | 4–40 cm × 0.2–0.5 mm. |
2–20 cm × 0.2–0.3 mm. |
Leaves | sometimes sparsely orange-punctate at 10–15X; sheaths usually reddish proximally; distal blade rudimentary to much longer than sheath, often exceeding culm, to 20 cm × 0.2–1 mm. |
sheaths green to stramineous; distal blade mostly much longer than sheath, to 3 cm × 0.2 mm. |
Inflorescences | involucral bract 1, sometimes subtending flower or resembling enlarged floral scale, 2–6(–23) mm. |
involucral bract 1, 3–10(–25) mm, rarely a second bract to 5 mm. |
Spikelets | 2–5 × 1–2 mm; scales partly or completely dark orange to red-brown, rarely stramineous, midrib greenish to stramineous, not gibbous, obscurely to prominently 3–11-veined, midrib keeled near apex, membranous, hyaline, apex rounded to acute, with mucro less than 0.1 mm; proximal scale to 2 mm; other scales 1.2–1.8 × 1–1.3 mm. |
2–8 × 1–1.5 mm; scales colorless, stramineous, or pale greenish, markedly gibbous, veinless or obscurely 3–7-veined, midrib keeled, finely reticulate at 40X, membranous, hyaline, apex rounded, mucronate, or awned; proximal scale to 1.5(–5) mm, awn to 3 mm; other scales 1–1.2 mm, apex, mucro 0.1 mm. |
Flowers | anthers 0.3–0.6 mm; styles 3-fid or 3-fid and 2-fid. |
anthers 0.2 mm; styles 3-fid. |
Achenes | falling separately from scales, medium to dark brown or stramineous, ellipsoid to obovoid, compressed-trigonous to thickly biconvex, lateral angles usually prominent, abaxial angle prominent to obscure, faces convex or adaxial face slightly concave, 0.8–1 × 0.5–0.7 mm, distinctly papillose at 10–15X to obscurely papillose at 40X, often with thin whitish surface layer. |
often falling with and clasped by floral scales, whitish (or orange-brown when unripe), broadly ellipsoid to obovoid or outline subcircular, nearly equilaterally trigonous, faces convex, 0.7–0.9 × 0.5–0.6 mm, minutely papillose at 40X, papillae in many vertical rows or usually obscured by thick whitish surface layer. |
2n | = 30. |
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Isolepis cernua |
Isolepis pseudosetacea |
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Phenology | Fruiting late spring–winter (Pacific Coast), winter–spring (Texas). | Fruiting spring–summer. |
Habitat | Wet, freshwater to brackish places on beaches, dunes, marine bluffs, sandy areas, mostly coastal | Wet, freshwater, often drying, places in grasslands, open woods, limestone barrens, cultivated fields, waste places |
Elevation | 0–800 m (0–2600 ft) | 0(–100) m (0(–300) ft) |
Distribution |
CA; OR; TX; WA; BC; Mexico (Baja California); temperate South America; Eurasia; Africa; Australia; New Zealand
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AL; AR; GA; LA; MO; MS; TX; s Europe; n Africa |
Discussion | Isolepis cernua is widespread and variable. Four varieties were recognized by A. M. Muasya and D. M. Simpson (2002). Only var. ceruna is known from North America. The earliest collection I have seen from the Pacific Coast is from 1888; the earliest collection I have seen from Texas is from 1974. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Isolepis pseudosetacea is often mistaken for the very similar I. carinata, with which it sometimes grows but does not intergrade. It may easily be distinguished by the characters given in the key. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 139. | FNA vol. 23, p. 138. |
Parent taxa | Cyperaceae > Isolepis | Cyperaceae > Isolepis |
Sibling taxa | ||
Synonyms | Scirpus cernuus, Scirpus cernuus var. californicus, Scirpus cernuus subsp. californicus | Scirpus pseudosetaceus, I. molesta, Scirpus molestus |
Name authority | (Vahl) Roemer & Schultes: in J. J. Roemer et al., Syst. Veg. 2: 106. (1817) | (Daveau) Gandoger: Cat. Pl. Espagne, 331. (1917) |
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