Cyperus pseudothyrsiflorus

(Kükenthal) J. Rich. Carter & S. D. Jones

Rhodora 99: 330. 1998.

Illustrated
Basionym: Cyperus uniflorus var. pseudothyrsiflorus Kükenthal in H. G. A. Engler, Pflanzenr. 101[IV,20]: 521. 1936
Treatment appears in FNA Volume 23. Mentioned on page 185.
Revision as of 00:38, 30 July 2020 by imported>Volume Importer
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Herbs, perennial, cespitose, rhizomatous. Culms trigonous, base thickened, tuberous, 15–40 cm × 2–2.6 mm, glabrous. Leaves flat to V-shaped, 10–30 cm × (3–) 4–5.8 mm. Inflorescences: spike 1, densely oblong to ellipsoid, 10–20 × 10–20 mm; rays 4–12, 10–20 cm bracts 3–6, horizontal to ascending at 30°, V-shaped, 3–15 cm × (3–) 4 (–5.8) mm; rachilla deciduous, wings persistent, 0.5–0.7 mm wide. Spikelets (5–) 10–20 (–30), linear to oblong, quadrangular, (2.2–) 4–12 (–16) × 0.7–1.2 mm, densly packed on rachis with 11–21 spikelets per 5 mm rachis; distal spikelet spreading or ascending; floral scales persistent, 1–5, appressed, laterally whitish to reddish-brown, medially green, narrowly oblong to ovate, laterally 3–6-ribbed, 2.4–3.4 × 1.6–2 mm, apex rounded to ± acute, entire, mucronate, mucro 0.1–0.3 mm; sterile terminal scale, involute, only 0.4–0.6 mm wide with mucro 0.2–0.5 mm. Flowers: anthers (0.3–) 0.4–0.7 mm; styles 0.4–0.5 mm; stigmas 0.5–0.9 mm. Achenes light-brown, sessile to slightly stipitate, ellipsoid to narrowly ellipsoid to narrowly obovoid, 1.4–1.9 × 0.5–0.75 mm, apex slightly apiculate, surfaces puncticulate.


Phenology: Fruiting mid summer–early fall (Jul–Sep).
Habitat: Damp, disturbed soils, croplands
Elevation: 0–1000 m

Discussion

Selected References

None.

Lower Taxa

None.

"shortened" is not a number.

sessile +  and slightly stipitate +
light-brown +
0.14 cm1.4 mm <br />0.0014 m <br /> (0.19 cm1.9 mm <br />0.0019 m <br />) +
ellipsoid;narrowly ellipsoid +
0.5mm;0.75mm +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
apiculate +  and entire +
mucronate;rounded;more or less acute +
Gordon C. Tucker* +, Brian G. Marcks* +  and J. Richard Carter * +
(Kükenthal) J. Rich. Carter & S. D. Jones +
persistent +  and deciduous +
15 cm150 mm <br />0.15 m <br /> (40 cm400 mm <br />0.4 m <br />) +
decurrent +
2mm;2.6mm +
Cyperus uniflorus var. pseudothyrsiflorus +
w--shaped +  and keeled +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
0.4 cm4 mm <br />0.004 m <br /> (0.58 cm5.8 mm <br />0.0058 m <br />) +
3 cm30 mm <br />0.03 m <br /> (15 cm150 mm <br />0.15 m <br />) +
horizontal +  and ascending +
v--shaped +
4 cm40 mm <br />0.04 m <br /> (?) +
parallel +  and divergent +
terete +, rolled +  and plicate +
scabridulous +
trigonous +
ascending +  and spreading +
Tex. +  and Mexico +
0–1000 m +
green +, laterally whitish +  and reddish-brown +
0.24 cm2.4 mm <br />0.0024 m <br /> (0.34 cm3.4 mm <br />0.0034 m <br />) +
narrowly oblong +  and ovate +
0.16 cm1.6 mm <br />0.0016 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
hypogynous +  and subtending +
biconvex +  and trigonous +
Damp, disturbed soils, croplands +
subumbellate +  and capitate +
spreading +  and erect +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
10 cm100 mm <br />0.1 m <br /> (?) +  and 30 cm300 mm <br />0.3 m <br /> (?) +
flat +  and v-shaped +
0.4 cm4 mm <br />0.004 m <br /> (0.58 cm5.8 mm <br />0.0058 m <br />) +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
with (1-)3-6(-30) bristles and/or scales +
Fruiting mid summer–early fall (Jul–Sep). +
2-3(-4)-carpellate +
antrorse +  and extrorse +
3 (?) +  and 1 (?) +
continuous +, articulate +, winged +  and wingless +
conspicuous +
unequal +
4 +  and 12 +
10 cm100 mm <br />0.1 m <br /> (20 cm200 mm <br />0.2 m <br />) +
adventitious +
basal +  and proximal +
cylindric;compressed +
cylindric +
Illustrated +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
densely oblong;ellipsoid +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
1.2 cm12 mm <br />0.012 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
11 +  and 21 +
quadrangular;linear;oblong +
0.7mm;1.2mm +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.09 cm0.9 mm <br />9.0e-4 m <br />) +
2-3-fid +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
Undefined subg. Chlorocyperus +, Cyperus subg. Mariscus +  and Undefined subg. Papyrus +
Cyperus pseudothyrsiflorus +
Cyperus subg. Cyperus +
species +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
herb +  and cespitose +
persistent +
0.5mm +  and 0.7mm +