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fiberoptic grass, low bulrush, low clubrush, low lateral clubrush, tuft clubrush

Habit Plants annual (or perennial?); rhizomes usually obscured by culm bases and very short, sometimes vertical and elongated.

4–40 cm × 0.2–0.5 mm.


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.


involucral bract 1, sometimes subtending flower or resembling enlarged floral scale, 2–6(–23) mm.


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.


anthers 0.3–0.6 mm;

styles 3-fid or 3-fid and 2-fid.


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.


= 30.

Isolepis cernua

Phenology Fruiting late spring–winter (Pacific Coast), winter–spring (Texas).
Habitat Wet, freshwater to brackish places on beaches, dunes, marine bluffs, sandy areas, mostly coastal
Elevation 0–800 m [0–2600 ft]

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.)

from FNA
CA; OR; TX; WA; BC; Mexico (Baja California); temperate South America; Eurasia; Africa; Australia; New Zealand
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Parent taxa Cyperaceae > Isolepis
Sibling taxa
I. carinata, I. pseudosetacea, I. setacea
Synonyms Scirpus cernuus, Scirpus cernuus var. californicus, Scirpus cernuus subsp. californicus
Name authority (Vahl) Roemer & Schultes: in J. J. Roemer et al., Syst. Veg. 2: 106. (1817)
Source Flora of North America vol. 23, p. 139.
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