keys to the vascular plants of east texas - Botanical Research ...

602 CYPERACEAE/ELEOCHARIS
name E. ravenelii. Smith (2002d) noted that this species is apparently very uncommon, and
that it closely resembles and is sometimes mistaken for slender-stemmed individuals of E.
montana; that species can be distinguished by its spikelet scales 1.5 mm or more long and 100–
500 per spikelet, its mostly larger and biconvex achenes, and its culm septa usually visible externally.
Carr (2001) and Poole et al. (2002) recognized E. austrotexana and considered it a TX
endemic and of conservation concern (G3, S3). While we are synonymizing E. austrotexana
with E. ravenelii, because of its rareness in the state, we still consider the taxon to be of conservation
concern in TX. �
Eleocharis reverchonii Svenson, (for Julien Reverchon, 1837–1905, a French-American immigrant
to Dallas and important botanical collector of early TX), REVERCHON’S SPIKE-RUSH. Perennial,
rhizomatous (though not always evident); culms 25 cm or less tall; distal leaf sheath with
apex blunt; spikelets 2–6 mm long, ovoid, with 5–15 scales, rarely proliferating (Smith 2002d);
achenes trigonous, 0.5–0.7 mm long, longitudinally ridged, with many horizontal lines between
the ridges; tubercle 0.15 mm or less long. Open wet areas; Dallas, Upshur (BRIT), Bastrop,
Bexar, Caldwell, and Travis (Turner et al. 2003) cos.; sparsely scattered elsewhere in TX; apparently
endemic to TX (Smith 2002d). Feb–Apr. This species is sometimes synonymized with E.
acicularis (e.g., Correll & Johnston 1970; Hatch et al. 1990; Diggs et al. 1999) and Smith (2002d)
noted that it “perhaps should be treated as a variety or subspecies of E. acicularis.” However, we
are following the recent treatment in Smith (2002d) who recognized it as a distinct species; he
also indicated that it is of conservation concern. E �
Eleocharis rostellata (Torr.) Torr., (with a small beak), BEAKED SPIKE-RUSH. Densely tufted and
stoloniferous perennial, mat-forming; culms 25–80(–100) cm tall, some (stolons) arching or decumbent
and taking root at the tip; distal leaf sheath with apex angled to a broad short point
on one side; spikelets (5–)8–20 mm long, ovoid, sometimes proliferous, with 20–40 scales;
achenes trigonous, variable, 1.5–1.8(–2.5) mm long; tubercle 0.5 mm or less long, � appearing as
a continuation of the achene, sometimes rudimentary or absent. Marshes, shorelines, other wet
areas, brackish or alkaline conditions; Travis (BRIT), DeWitt, Gonzales, and Hays (Turner et al.
2003) cos. near s margin of East TX; mainly w 1/2 of TX; s Canada and widespread in the U.S.
Apr–Aug. [Scirpus rostellatus Torr.] Smith (2002d) noted that this species can be highly competitive,
sometimes forming large monospecific colonies.
Eleocharis tenuis (Willd.) Schult. var. verrucosa (Svenson) Svenson (sp.: slender; var.: covered
with warts), SLENDER SPIKE-RUSH. Rhizomatous perennial, mat-forming; distal leaf sheath apex
truncate or slightly angled to a broad short point on one side, rarely with a minute tooth; culms
ca. 5–40 cm tall; spikelets 3–6 mm long, ovoid, with 20–60 scales; achenes trigonous, 0.6–0.9
mm long, honey-combed when examined with hand lens; tubercles depressed. Ditches, other
wet areas; scattered in Pineywoods and Post Oak Savannah; also in n Gulf Prairies and Marshes;
widespread in e 1/2 of the U.S. Mar–Jun. [E. capitata (L.) R. Brown var. verrucosa Svenson, E.
verrucosa (Svenson) L.J. Harms] Yatskievych (1999) treated this taxon as a distinct species (E.
verrucosa). However, according to Smith (2002d), “Harms used chromosome number as a basis
for raising Eleocharis tenuis var. verrucosa to a species (L.J. Harms 1972), but he did not correlate
chromosomes with morphology. There are too few chromosome number reports for use in
defining taxa in the E. tenuis complex (A.E. Schuyler 1977).” Of the three varieties recognized in
North America, only var. verrucosa is known to occur in TX (Smith 2002d).
Eleocharis tortilis (Link) Schult., (twisted), TWISTED SPIKE-RUSH. Clump-forming perennial, with
ascending rhizomes; culms 15–80 cm tall; distal leaf sheath with apex angled to a short point
on one side; spikelets (4–)6–14 mm long, ovoid to lanceoloid or ellipsoid, with 10–25 scales; perianth
bristles retrorsely barbed; achenes trigonous, 1.2–1.7(–2.4) mm long, coarsely honeycombed
reticulate; tubercle 0.3–0.7(–1) mm long. Bogs, seeps, ditches, other wet places, sometimes
emergent; widespread in East TX; se U.S. from MD s to FL w to AR and TX. May–Oct.
[Scirpus tortilis Link] Smith (2002d) noted that “Eleocharis tortilis differs consistently from E.