Eleocharis equisetoides

(Elliott) Torrey

Ann. Lyceum Nat. Hist. New York 3: 296. 1836.

Common names: Horsetail spike-rush jointed spike-rush (spikesedge) knotted spike-rush
IllustratedEndemic
Basionym: Scirpus equisetoides Elliott Sketch Bot. S. Carolina 1: 79. 1816
Synonyms: Eleocharis elliottii A. Dietrich
Treatment appears in FNA Volume 23. Mentioned on page 120.

Plants perennial; rhizomes 2–4 mm thick, soft to firm, longer internodes 2–8 cm, scales persistent, 7–8 mm, membranous, tubers absent. Culms terete, 50–100 cm × 5–8.4 mm, soft to firm, obscurely to clearly septate-nodulose throughout, internally hollow with complete transverse septa, closer together near the spikelet; plants never forming filiform, flaccid culms. Leaves: distal leaf-sheaths persistent, membranous to thinly papery, apex acute to slightly acuminate. Spikelets not proliferous, 20–45 × 4–5 (–8) mm; rachilla joints bearing prominent winglike remnants of floral scales; proximal scale empty, amplexicaulous, (2–) 2.8–4.9 mm; floral scales 85–160, 1–3 per mm of rachilla, stramineous to pale-brown, usually with pale to dark-brown submarginal band, obovate to oblong, (4.8–) 5.2–7 × 3–4.4 mm, cartilaginous, often membranous toward margins, margins broadly translucent, membranous, apex rounded to obtuse. Flowers: perianth bristles 3–8, stramineous to reddish, slender, vestigial to 2.5 mm, shorter than to equaling achene, smooth or obscurely retrorsely spinulose; anthers stramineous to red-striated, 2.6–3.2 mm; styles 2–3-fid. Achenes yellowish to reddish-brown, obovoid, biconvex to obscurely compressed trigonous, 1.8–2.3 × 1.4–1.9 mm, obscurely sculptured or sometimes partially smooth at 10–15X, each face with 20–40 rows of linear, transversely elongated cells, lines separating cells obscure, apex with very short neck 0.6–0.8 mm wide. Tubercles dark-brown, lamelliform, high-deltoid, 0.6–1.1 × 0.5–0.7 mm.


Phenology: Fruiting late spring–late fall.
Habitat: Fresh ponds, lakes, marshes, streams, ditches, cypress swamps
Elevation: 10–500 m

Distribution

V23 182-distribution-map.jpg

Ont., Ala., Calif., Conn., Fla., Ga., Ind., La., Md., Mass., Mich., Miss., Mo., N.Y., N.C., R.I., S.C., Tex., Va., Wis.

Discussion

We have not seen voucher specimens for reports of Eleocharis equistoides from Arkansas and Tennessee. It is probably extirpated from Illinois, Missouri, and Wisconsin.

Contrary to previous decriptions, sectioning of the culm reveals that the distance between the septa near the spikelet cannot be used to distinguish the two septate species, E. equisetoides and E. interstincta, which when achenes are absent are better distinguished by the septate-nodulose distal parts of the culms of E. equisetiodes.

Selected References

None.

Lower Taxa

None.
... more about "Eleocharis equisetoides"
yellowish +  and reddish-brown +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
sculptured +
trigonous;biconvex;obscurely compressed +
constricted +
1.4mm;1.9mm +
stramineous;red-striated +
0.26 cm2.6 mm <br />0.0026 m <br /> (0.32 cm3.2 mm <br />0.0032 m <br />) +
M. Socorro González-Elizondo +
(Elliott) Torrey +
flattened +
0 cm0 mm <br />0 m <br /> (6 cm60 mm <br />0.06 m <br />) +
shortened +
persistent +
enlarged +
Scirpus equisetoides +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
ascending +  and appressed +
parallel +  and divergent +
terete +, rolled +  and plicate +
enlarged +
Horsetail spike-rush +, jointed spike-rush (spikesedge) +  and knotted spike-rush +
50 cm500 mm <br />0.5 m <br /> (100 cm1,000 mm <br />1 m <br />) +
filiform +, septate-nodulose +  and terete +
flaccid;soft;firm +
5mm;8.4mm +
Ont. +, Ala. +, Calif. +, Conn. +, Fla. +, Ga. +, Ind. +, La. +, Md. +, Mass. +, Mich. +, Miss. +, Mo. +, N.Y. +, N.C. +, R.I. +, S.C. +, Tex. +, Va. +  and Wis. +
10–500 m +
0.48 cm4.8 mm <br />0.0048 m <br /> (0.52 cm5.2 mm <br />0.0052 m <br />) +
stramineous +  and pale-brown +
0.52 cm5.2 mm <br />0.0052 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
obovate +  and oblong +
0.3 cm3 mm <br />0.003 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.44 cm4.4 mm <br />0.0044 m <br />) +
subtending +
biconvex +  and trigonous +
Fresh ponds, lakes, marshes, streams, ditches, cypress swamps +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
2 cm20 mm <br />0.02 m <br /> (8 cm80 mm <br />0.08 m <br />) +
flattened +
0 cm0 mm <br />0 m <br /> (6 cm60 mm <br />0.06 m <br />) +
distinct +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (?) +  and 0.08 cm0.8 mm <br />8.0e-4 m <br /> (?) +
spinulose +  and smooth +
0 cm0 mm <br />0 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
with (1-)3-6(-30) bristles and/or scales +
Fruiting late spring–late fall. +
2-3(-4)-carpellate +
3 (?) +  and 1 (?) +
amplexicaulous +  and empty +
0.2 cm2 mm <br />0.002 m <br /> (0.28 cm2.8 mm <br />0.0028 m <br />) +
stramineous;medium brown or red brown or blackish brown +
0.28 cm2.8 mm <br />0.0028 m <br /> (0.49 cm4.9 mm <br />0.0049 m <br />) +
Ann. Lyceum Nat. Hist. New York +
ascending +  and horizontal +
caudex-like +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
adventitious +
persistent +
basal +  and proximal +
2-keeled +
0.7 cm7 mm <br />0.007 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
membranous +
cylindric +
Illustrated +  and Endemic +
0.5 cm5 mm <br />0.005 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
2 cm20 mm <br />0.02 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
not proliferous +
terete;cylindric;narrowly ellipsoid +
0.9 cm9 mm <br />0.009 m <br /> (7.5 cm75 mm <br />0.075 m <br />) +
1 (?) +  and 3 (?) +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
2-3-fid +
pale +  and dark-brown +
Eleocharis elliottii +
Eleocharis equisetoides +
Eleocharis subg. Limnochloa +
species +
0.6mm;1.1mm +
high-deltoid +  and lamelliform +
0.5mm +  and 0.7mm +
stoloniferous +  and rhizomatous +