Eleocharis engelmannii |
Eleocharis tenuis |
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Engelmann's spikerush |
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Habit | Plants annual, tufted. | |
Culms | terete, 2–40 cm × 0.5–1.5(2) mm. |
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Spikes | lanceoloid to subcylindric, 5–10(20) × 2–3(4) mm; proximal scale empty, encircling approximately 67% of culm; floral scales 25–100(200), 8–12 per mm of rachilla, 2(2.5) × 1–1.3 mm; apex narrowly rounded to subacute. |
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Flowers | perianth bristles present or often absent; (0)5–8; about as long as the achenes; anthers 0.3–0.7(1) mm; stigmas 2–3. |
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Achenes | biconvex or to 33% greatly compressed trigonous, 0.9–1.1(1.5) × 0.7– 1.1 mm. |
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Distal leaf sheaths | persistent, apex of distal leaf sheath obtuse to acute, with tooth to 0.3 mm. |
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Tubercles | depressed, subdeltoid, 0.1–0.3(0.4) × 0.6–0.9(1) mm, 10–40% as high as wide, 25% or less as high as achene, 90% as wide as achene. |
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Eleocharis engelmannii |
Eleocharis tenuis |
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Distribution | ||
Discussion | Freshwater shores exposed by seasonal low water levels, marshes, disturbed wetlands. 50–500 m. WV. CA, ID, WA; north to British Columbia, east to MA, southeast to AL. Native. Eleocharis engelmannii is similar to E. ovata and the much more common E. obtusa but has markedly shorter tubercles and usually more cylindric spikes. |
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Source | Flora of Oregon, volume 1, page 241 Barbara Wilson, Richard Brainerd, Nick Otting |
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Sibling taxa | ||
Synonyms | Eleocharis engelmannii var. engelmannii, Eleocharis engelmannii var. monticola, Eleocharis obtusa var. engelmannii | |
Web links |
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