Carex opaca

(F. J. Hermann) P. E. Rothrock & Reznicek

Novon 11: 223. 2001.

IllustratedEndemic
Basionym: Carex bicknellii var. opaca F. J. Hermann Sida 5: 49. 1972
Treatment appears in FNA Volume 23. Treatment on page 375. Mentioned on page 338.

Plants densely cespitose, to 200 culms together; rhizomes appearing elongate only in old clumps. Culms 50–115 cm; vegetative culms few, inconspicuous, usually fewer than 12 leaves, not strikingly 3-ranked. Leaves: sheaths glabrous, hyaline sometimes brown tinged band near collar, the summits U-shaped to truncate, ± equaling the base of the blade; distal ligules 1.5–5.4 mm; blades 3–6 per fertile culm, 3.5–40 cm × 1.5–4.6 mm. Inflorescences open, erect to slightly arching, pale or golden brown, 2.4–5.5 (–6.4) cm × 6.5–21 mm; proximal internode 4–13 (–18) mm; 2d internode 3–11 mm; proximal bracts scalelike, with bristle tips to 1.5 cm. Spikes 4–8 (–10), distinct, ovoid, 10–22 × 4–11 mm, base rounded to tapered, apex rounded to acute. Pistillate scales pale-brown with narrow yellow-green to brown midstripe, lanceolate to narrowly ovate, (3.6–) 3.9–5 mm, 2.4–3.1 (–3.4) times as long as wide, barely or not reaching base of perigynium beaks, margin hyaline, apex firm and herbaceous, flat or inrolled, obtuse to acute. Staminate scales obtuse to acuminate. Anthers (1.8–) 2.2–3.6 mm. Perigynia 15–80 in larger spikes, ± appressed, yellowish green to brown with paler margins, conspicuously 3–7-veined adaxially, 8–12-veined abaxially, 2–5 veins in wings, broadly ovate, broadly elliptic, or orbiculate, often strongly concave, (5.6–) 6–7.1 × 3.3–4.6 (–4.8) mm, 0.5–0.7 mm thick, margin flat, including wing 0.6–1.3 mm wide, smooth; beak pale or golden brown at tip, strongly flattened, (1.2–) 1.5–2.1 (–2.3) mm, serrulate-margined to apex, abaxial suture yellow-green to copper-brown, distance from tip of beak to achene 2.8–4 mm. Achenes broadly ovate to oblong, 1.8–2.4 × 1.3–1.9 mm, 0.5–0.7 mm thick, apiculum to 0.5–1.1 mm. 2n = 66, 68.


Phenology: Fruiting early summer.
Habitat: Low areas in prairies, roadside ditches, poorly drained sites
Elevation: 50–400 m

Distribution

V23 665-distribution-map.jpg

Ark., Ill., Kans., Miss., Mo., Okla.

Discussion

Selected References

None.

Lower Taxa

None.

"+timesaslongasinflorescences" is not declared as a valid unit of measurement for this property."not undefined" is not a number.

... more about "Carex opaca"
yellow-green +  and copper-brown +
broadly ovate;oblong +
smaller +
0.5mm +  and 0.7mm +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
0.22 cm2.2 mm <br />0.0022 m <br /> (0.36 cm3.6 mm <br />0.0036 m <br />) +
bidentatate +
papillose +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
Joy Mastrogiuseppe +, Paul E. Rothrock +, A. C. Dibble +  and A. A. Reznicek +
(F. J. Hermann) P. E. Rothrock & Reznicek +
shortened +
brown tinged +  and hyaline +
persistent +
rounded +  and tapered +
not enlarged +
Carex bicknellii var. opaca +
serrulate-margined +
0.21 cm2.1 mm <br />0.0021 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
flattened +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.21 cm2.1 mm <br />0.0021 m <br />) +
3.5 cm35 mm <br />0.035 m <br /> (40 cm400 mm <br />0.4 m <br />) +
3 (?) +  and 6 (?) +
v--shaped +
1.5mm;4.6mm +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
ascending +  and appressed +
scale-like +  and leaflike +
0 cm0 mm <br />0 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
parallel +  and divergent +
terete +, rolled +  and plicate +
inconspicuous +
fertile +  and vegetative +
round +  and trigonous +
50 cm500 mm <br />0.5 m <br /> (115 cm1,150 mm <br />1.15 m <br />) +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.54 cm5.4 mm <br />0.0054 m <br />) +
Ark. +, Ill. +, Kans. +, Miss. +, Mo. +  and Okla. +
50–400 m +
open +, pistillate +  and staminate +
hypogynous +  and subtending +
biconvex +  and trigonous +
Low areas in prairies, roadside ditches, poorly drained sites +
5.5 cm55 mm <br />0.055 m <br /> (6.4 cm64 mm <br />0.064 m <br />) +
golden brown +  and pale +
erect +  and slightly arching +
0.3 cm3 mm <br />0.003 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
not prophyllate +, sessile +  and pistillate +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
basal +  and cauline +
paler +  and hyaline +
0.6mm +  and 1.3mm +
yellow-green +  and brown +
with (1-)3-6(-30) bristles and/or scales +
8-12-veined +  and 3-7-veined +
yellowish green +  and brown +
erect +  and spreading +
Fruiting early summer. +
2-3(-4)-carpellate +
3 (?) +  and 1 (?) +
sheathless +  and bristlelike +
0.4 cm4 mm <br />0.004 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
adventitious +
staminate +  and pistillate +
0.36 cm3.6 mm <br />0.0036 m <br /> (0.39 cm3.9 mm <br />0.0039 m <br />) +
2.4-3.1(-3.4) +
basal +  and proximal +
obtuse;acuminate +
0.39 cm3.9 mm <br />0.0039 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
herbaceous +  and membranous +
not differentiated +
cylindric +
Illustrated +  and Endemic +
distinct +
1 cm10 mm <br />0.01 m <br /> (2.2 cm22 mm <br />0.022 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
1 (?) +  and 3 (?) +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
deciduous +  and persistent +
2-3(-4)-fid +
u-shaped +  and truncate +
Carex opaca +
Carex sect. Ovales +
species +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
plant +  and cespitose +