Eleocharis bolanderi |
Eleocharis quadrangulata |
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Bolander's spikerush |
four-angle spikerush, square-stem spike-rush, square-stem spikesedge |
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Habit | Plants perennial, densely tufted; rhizomes caudexlike, mostly hidden by culms and roots, short, 1.5–3 mm thick, hard, cortex persistent, internodes very short, scales not evident. | Plants perennial; rhizomes 1.5–4 mm thick, soft to hard, longer internodes 3–8 cm, scales 5–10 mm, tubers absent. |
Culms | subterete, often with to 6 prominent ridges when dry, sulcate, 10–30 cm × 0.3–0.5 mm, firm to rigid, spongy. |
acutely quadrangular, (30–)45–105 cm × (1–)2–5.4 mm, soft to firm, internally spongy, transverse septa incomplete; plants never forming filiform, flaccid culms. |
Leaves | distal leaf sheaths persistent, not splitting, proximally brown, red, or stramineous, distally stramineous, green or reddish, papery, apex sometimes reddish, obtuse, rarely callose, tooth absent. |
distal leaf sheaths persistent, membranous, apex narrowly acute to acuminate, sometimes prolonged into a bladelike portion to 8 cm. |
Spikelets | ovoid, 3–8 × 2–3 mm, apex acute to obtuse; proximal scale amplexicaulous, entire; subproximal scale with flower; floral scales spreading in fruit, 8–30, 4–5 per mm of rachilla, dark brown to blackish, midrib regions often stramineous or greenish, ovate to lanceolate, 2–3 × 1.5 mm, apex entire, acute, often carinate in distal part of spikelet. |
not proliferous, (15–)20–76 × 3–5(–6) mm; rachilla joints bearing obscure winglike remnants of floral scales; proximal scale empty, amplexicaulous, (1–)2.2–5.4 mm; floral scales (28–)45–135, 2–3 per mm of rachilla, stramineous to pale brown, usually with pale to dark brown submarginal band, midrib region sometimes greenish, broadly obovate to ovate, (4–)4.5–6.2 × 2.8–5 mm, subcartilaginous, apex rounded to obtuse. |
Flowers | perianth bristles 3–6, whitish to stramineous, stout to slender, often unequal, from rudimentary to 1/2 of achene length; stamens 3; anthers dark yellow to brown, 0.9–1.4 mm; styles 3-fid. |
perianth bristles 6–7, whitish to brown, slender, often markedly unequal, shorter than achene or some equalling tubercle, sparsely retrorsely spinulose to smooth; anthers stramineous to red-brown, 2.3–2.9 mm; styles 3-fid, sometimes 2-fid. |
Achenes | falling with scales, stramineous, rarely dark brown, ovoid to obpyriform, slightly to greatly compressed-trigonous, rarely thickly lenticular, angles prominent or abaxial angle obscure, 0.9–1.2 × 0.65–0.8 mm, apex narrowly to broadly truncate, neck short, often compressed more than body, at 20–30X finely rugulose with more than 20 horizontal ridges in a vertical series or reticulate or cancellate. |
yellow or pale green to brown or purplish, biconvex, obovoid to obpyriform, 1.8–3 × 1.3–2 mm, almost smooth to markedly sculptured at 10–15X, each face with 19–38 rows of almost linear, transversely elongated cells, which are sometimes isodiametric at achene base, apex often constricted to neck 0.3–0.4 mm wide. |
Tubercles | whitish to brown, pyramidal, lower than wide, often 3-lobed as viewed from the top, 0.1–0.3 × 0.4–0.65 mm. |
dark brown or whitish, deltoid to high-pyramidal or lanceoloid, 0.7–1.5 × 0.4–1 mm, often spongy. |
Eleocharis bolanderi |
Eleocharis quadrangulata |
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Phenology | Fruiting late spring–summer. | Fruiting early summer–winter. |
Habitat | Fresh, often summer-dry meadows, springs, seeps, stream margins | Shallow water of fresh lake and pond shores, marshes |
Elevation | 1000–3400 m (3300–11200 ft) | 10–600 m (0–2000 ft) |
Distribution |
CA; CO; ID; NV; OR; UT
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AR; CA; CT; DE; FL; GA; IL; IN; KY; LA; MA; MI; MO; MS; NC; NJ; NY; OH; OK; OR; PA; SC; TX; VA; WI; WV; ON; s to c Mexico
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Discussion | Eleocharis bolanderi is clearly distinct from E. montevidensis, from which it differs in its dense, tufted habit with short, caudexlike rhizomes, its leaf sheaths without a tooth, its achene and tubercle shapes, and its acute floral scales. Specimens of Eleocharis bolanderi without rhizomes or achenes are easily confused with E. decumbens, which often may be distinguished by culms 0.5–2 mm wide, and spikelets with scales sometimes more than 3 mm long. The tubercles of E. bolanderi are usually poorly developed and much lower than wide; in E. decumbens they are usually well developed and about as high as wide. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
We have not seen voucher specimens for the reports of Eleocharis quadrangulata from Kansas. Plants with greenish achenes, longer bristles, and longer anthers than the average are known from Tennessee. The tubercles of Eleocharis quadrangulata are often spongy as in E. obtusetrigona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23. | FNA vol. 23, p. 120. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis | Cyperaceae > Eleocharis > subg. Limnochloa |
Sibling taxa | ||
Synonyms | E. montevidensis var. bolanderi | Scirpus quadrangulatus, E. quadrangulata var. crassior, Scirpus albomarginatus, Scirpus marginatus |
Name authority | A. Gray: Proc. Amer. Acad. Arts 7: 392. (1868) | (Michaux) Roemer & Schultes: in J. J. Roemer et al., Syst. Veg. 2: 155. (1817) |
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