Scirpus flaccidifolius

(Fernald) Schuyler

Rhodora 69: 198. 1967.

IllustratedEndemicConservation concern
Basionym: Scirpus atrovirens var. flaccidifolius Fernald Rhodora 40: 396. 1938
Treatment appears in FNA Volume 23. Treatment on page 13. Mentioned on page 11, 12, 14, 15.
Revision as of 01:01, 30 July 2020 by imported>Volume Importer
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Plants cespitose; rhizomes short, tough, fibrous. Culms: fertile ones lax, reclining, inflorescences lopping over to (or nearly to) ground; nodes without axillary bulblets. Leaves 7–11 per culm; sheaths of proximal leaves light-brown or whitish; proximal sheaths and blades with septa few-to-many, conspicuous or not; blades 30–63 cm × 9–14 mm. Inflorescences terminal, rarely also with 1 lateral inflorescence from distal leaf-axil; rays ascending or divaricate (usually both in same inflorescence), proximal branches smooth, distal branches smooth or scabrellous, rays often bearing axillary bulblets; bases of involucral-bracts green or margins brown or at least speckled with redbrown, not glutinous. Spikelets in dense clusters of 3–19 (largest cluster with 12 or more), spikelets sessile, ovoid or broadly ovoid, 3–4 × 2–3 mm; scales blackish with pale midribs, elliptic or broadly elliptic, 1.3–1.9 mm, apex mucronate, mucro 0.1–0.2 mm. Flowers: perianth bristles persistent, 6, slender, straight or curved, shorter than to slightly exceeding achene, with retrorse, thin-walled, round-tipped barbs in distal 0.2–0.5, enclosed within scales; styles 3-fid. Achenes almost white, elliptic or obovate in outline, planoconvex or plumply trigonous, 1–1.2 × 0.4–0.6 mm. 2n = 54.


Phenology: Fruiting late spring–early summer (Jun).
Habitat: Wooded bottomlands
Elevation: 10–20 m

Discussion

Of conservation concern.

Scirpus flaccidifolius is the most distinctive member of the S. atrovirens complex. The structure of the inflorescence is similar in all of these species, with a few long, nearly erect rays and many shorter, spreading to reflexed rays. The length of the rays is very variable in S. flaccidifolius, as in related species, but they may be very long in S. flaccidifolius, with the long, erect rays often being 15 cm or more (rarely to 25 cm).

Scirpus flaccidifolius is known from only six populations in its very limited range (less than 100 km across). It is very tolerant of human disturbance and does not seem to be declining.

Selected References

None.

Lower Taxa

None.

"shortened" is not a number.

... more about "Scirpus flaccidifolius"
0.1 cm1 mm <br />0.001 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
papillose +
trigonous;planoconvex;obovate;elliptic +
shorter to much +
0.4mm;0.6mm +
mucronate +
Alan T. Whittemore +  and Alfred E. Schuyler +
(Fernald) Schuyler +
round-tipped +  and thin-walled +
persistent +
Scirpus atrovirens var. flaccidifolius +
30 cm300 mm <br />0.3 m <br /> (63 cm630 mm <br />0.63 m <br />) +
keeled +, v--shaped +  and flat +
0.9 cm9 mm <br />0.009 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
ascending +  and appressed +
Barbed (?) +, Toothed (?) +  and Curled (?) +
parallel +  and divergent +
terete +, rolled +  and plicate +
trigonous +
scabrellous +  and smooth +
N.C. +  and Va. +
10–20 m +
hypogynous +  and subtending +
biconvex +  and trigonous +
Wooded bottomlands +
corymbose-paniculate +
speckled with redbrown +, at-least +  and brown +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
cauline +, all +  and basal +
whitish +  and light-brown +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
curved +  and straight +
with (1-)3-6(-30) bristles and/or scales +
Fruiting late spring–early summer (Jun). +
2-3(-4)-carpellate +
3 (?) +  and 1 (?) +
not +  and conspicuous +
divaricate +
adventitious +
2-keeled +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.19 cm1.9 mm <br />0.0019 m <br />) +
Few (?) +  and Many (?) +
cylindric +
not fibrous +
Illustrated +, Endemic +  and Conservation concern +
0 cm0 mm <br />0 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
50 +  and 500 +
ovoid;ovoid +
1 +  and 3 +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
Scirpus flaccidifolius +
species +
not +  and rhizomatous +
plant +  and cespitose +