Eleocharis ravenelii

Britton in J. K. Small

in J. K. Small, Fl. S.E. U.S., 184, 1327. 1903.

IllustratedConservation concern
Synonyms: Eleocharis austrotexana M. C. Johnston
Treatment appears in FNA Volume 23.

Plants perennial, densely tufted; rhizomes mostly hidden by aerial shoots and roots, not long, 2–3 mm thick, hard, cortex persistent?, internodes very short, scales persistent, 4–7 mm, membranous, slightly fibrous. Culms terete, when dry with to 12 blunt ribs, 20–55 cm × 0.5–1.1 mm, soft to firm, internally mostly hollow with complete transverse septa 2–4 mm apart, evident only on sectioning culm. Leaves: distal leaf-sheaths persistent, not splitting, proximally dark red, distally stramineous or reddish, thinly papery, apex often red to brown, obtuse to subtruncate, slightly callose, tooth present, 0.5–1 (–3.7) mm. Spikelets lanceoloid, 5–13 × 2–2.5 mm, apex acute to obtuse; proximal scale amplexicaulous, entire; subproximal scale empty; floral scales appressed in fruit, 10–100, 10–12 per mm of rachilla, medium brown to stramineous, midrib regions often greenish, ovate, 1–1.5 × 1 mm, entire, apex rounded to subacute, carinate in distal part of spikelet. Flowers: perianth bristles 5–6, pale-brown, stout, equaling achene; stamens 3; anthers brown, 0.4–0.9 mm; styles 3-fid or a few 2-fid in the same spikelet. Achenes falling with scales, green or medium or dark-brown, obpyriform, compressedtrigonous or some biconvex in same spikelet, angles prominent, 0.6–0.8 × 0.5–0.6 mm, neck short or absent, smooth or very finely reticulate at 20–30X. Tubercles brown, depressed-pyramidal, 0.1–0.2 × 0.2–0.3 mm.


Phenology: Fruiting spring–fall.
Habitat: Fresh, wet to damp, seasonally wet depressions, flatwoods, ditches
Elevation: 0–200 m

Distribution

V23 106-distribution-map.jpg

Tex., Mexico (San Luis Potosí)

Discussion

Of conservation concern.

Eleocharis ravenelii is apparently very uncommon in North America. It is often mistaken for very slender-stemmed E. montana, which differs in its spikelets with floral scales 1.5 mm or more, 100–500 per spikelet and 15–40 per mm of rachilla, its mostly larger and biconvex achenes, and its culm septa usually evident without sectioning the culm. Although the holotype of E. ravenelii (NY), from Corpus Christi, Texas, lacks culm bases and leaf sheaths, its culms, spikelets, floral scales, and achenes are typical of the later E. austrotexana M. C. Johnston.

Selected References

None.

Lower Taxa

None.
... more about "Eleocharis ravenelii"
dark-brown +  and green +
cancellate or reticulate +  and rugulose +
biconvex;obpyriform +
color +  and texture +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
0.5mm;0.6mm +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.09 cm0.9 mm <br />9.0e-4 m <br />) +
red +  and brown +
S. Galen Smith* +, Jeremy J. Bruhl* +, M. Socorro González-Elizondo* +  and Francis J. Menapace* +
Britton in J. K. Small +
flattened +
0 cm0 mm <br />0 m <br /> (6 cm60 mm <br />0.06 m <br />) +
shortened +
persistent +
enlarged +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
ascending +  and appressed +
parallel +  and divergent +
terete +, rolled +  and plicate +
persistent +
20 cm200 mm <br />0.2 m <br /> (55 cm550 mm <br />0.55 m <br />) +
soft;firm +
0.5mm;1.1mm +
reddish +, stramineous +  and dark red +
Tex. +  and Mexico (San Luis Potosí) +
0–200 m +
brown +  and stramineous +
membranous +  and thinly papery +
hypogynous +  and subtending +
biconvex +  and trigonous +
Fresh, wet to damp, seasonally wet depressions, flatwoods, ditches +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
1 cm10 mm <br />0.01 m <br /> (?) +
flattened +
0 cm0 mm <br />0 m <br /> (6 cm60 mm <br />0.06 m <br />) +
with (1-)3-6(-30) bristles and/or scales +
Fruiting spring–fall. +
2-3(-4)-carpellate +
3 (?) +  and 1 (?) +
stramineous;medium brown or red brown or blackish brown +
in J. K. Small, Fl. S.E. U.S., +
ascending +  and horizontal +
caudex-like +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
adventitious +
persistent +
basal +  and proximal +
2-keeled +
0.4 cm4 mm <br />0.004 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
fibrous +  and membranous +
0.2 cm2 mm <br />0.002 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
cylindric +
Illustrated +  and Conservation concern +
0.5 cm5 mm <br />0.005 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
lanceoloid +
2mm;2.5mm +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
2-fid +  and 3-fid +
Eleocharis austrotexana +
Eleocharis ravenelii +
Eleocharis (sect. Eleocharis) ser. Eleocharis +
species +
0.1 cm1 mm <br />0.001 m <br /> (0.37 cm3.7 mm <br />0.0037 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
0.1mm;0.2mm +
depressed-pyramidal +
0.2mm +  and 0.3mm +