Eleocharis engelmannii

Steudel

Syn. Pl. Glumac. 2: 79. 1855.

Common names: Engelmann’s spike-rush
IllustratedEndemic
Synonyms: Eleocharis engelmannii var. detonsa A. Gray Eleocharis engelmannii var. monticola (Fernald) Svenson Eleocharis engelmannii var. robusta Fernald Eleocharis monticola Eleocharis monticola var. leviseta Fernald Eleocharis ovata var. detonsa (A. Gray) Mohlenbrock
Treatment appears in FNA Volume 23. Treatment on page 104. Mentioned on page 64, 65, 105.

Culms 2–40 cm × 0.5–1.5(–2) mm. Leaves: apex of distal leaf sheath obtuse to acute, tooth to 0.3 mm. Spikelets lanceoloid to subcylindric or ovoid, 5–10(–20) × 2–3(–4) mm, apex acute (to rounded); proximal scale empty, encircling ca. 2/3 of culm; floral scales 25–100(–200), 8–12 per mm of rachilla, orangebrown to stramineous, 2(–2.5) × 1–1.3 mm, midribs mostly keeled, ovate, apex narrowly rounded to subacute. Flowers: perianth bristles present or often absent, 5–8, brown, stout, rudimentary to slightly exceeding tubercle; stamens (2–)3; anthers brown to yellow, 0.3–0.7(–1) mm; styles 2–3-fid. Achenes 0.9–1.1(–1.5) × 0.7–1.1 mm. Tubercles depressed, subdeltoid, 0.1–0.3(–0.4) × 0.6–0.9(–1) mm, 1/10–2/5 as high as wide, 1/4 or less as high as achene, 9/10 as wide as achene, very rarely 2/5 as high as achene (in E. engelmannii var. robusta). 2n = 10.


Phenology: Fruiting spring–fall.
Habitat: Fresh shores, marshes, disturbed places
Elevation: 30–2400 m

Distribution

V23 158-distribution-map.jpg

Alta., B.C., Man., Ont., Ala., Ariz., Ark., Calif., Colo., Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Kans., Ky., Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Mex., N.Y., N.Dak., Ohio, Okla., Oreg., Pa., R.I., Tenn., Tex., Va., Wash., W.Va., Wis.

Discussion

Robust plants known only from Missouri and described as Eleocharis engelmannii var. robusta have well-developed caudices, culms to 2 mm wide (pressed), spikelets to 2 cm, floral scales to 2.5 mm and slightly cartilaginous, styles mostly trifid, achenes to 1.5 × 1 mm, and tubercles 0.3–0.5 × 0.7–1 mm and to 2/5 as high as achene. Some specimens are intermediate between E. engelmannii and E. obtusa, or rarely with E. lanceolata. I have not seen specimens to verify literature reports of E. engelmannii from Manitoba, Connecticut, Delaware, Idaho, New Hampshire, North Carolina, Oregon, Rhode Island, South Carolina, South Dakota, or Vermont.

Selected References

None.

Lower Taxa

None.
... more about "Eleocharis engelmannii"
S. Galen Smith* +, Jeremy J. Bruhl* +, M. Socorro González-Elizondo* +  and Francis J. Menapace* +
Steudel +
Engelmann’s spike-rush +
Alta. +, B.C. +, Man. +, Ont. +, Ala. +, Ariz. +, Ark. +, Calif. +, Colo. +, Conn. +, Del. +, D.C. +, Idaho +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Mont. +, Nebr. +, N.H. +, N.J. +, N.Mex. +, N.Y. +, N.Dak. +, Ohio +, Okla. +, Oreg. +, Pa. +, R.I. +, Tenn. +, Tex. +, Va. +, Wash. +, W.Va. +  and Wis. +
30–2400 m +
Fresh shores, marshes, disturbed places +
Fruiting spring–fall. +
Syn. Pl. Glumac. +
Illustrated +  and Endemic +
Eleocharis engelmannii var. detonsa +, Eleocharis engelmannii var. monticola +, Eleocharis engelmannii var. robusta +, Eleocharis monticola +, Eleocharis monticola var. leviseta +  and Eleocharis ovata var. detonsa +
Eleocharis engelmannii +
Eleocharis (sect. Eleogenus) ser. Ovatae +
species +