Rhynchospora thornei

Kral

Sida 7: 42, fig. 1. 1977.

IllustratedEndemicConservation concern
Treatment appears in FNA Volume 23. Treatment on page 221. Mentioned on page 204, 220.
Please click on the illustration for a higher resolution version.
Illustrator:

Copyright:

Plants perennial, densely cespitose, 10–20 cm; rhizomes slender, short. Culms lax, filiform, leafy. Leaves spreading to ascending, exceeding or exceeded by culm; blades 0.2–0.3 mm wide, margins strongly involute or channeled, apex trigonous, tapering, setaceous. Inflorescences: cluster of cymes 1–2, widely spaced, turbinate, sparse; branches few; foliaceous bracts setaceous, longer than cymes. Spikelets brown, lanceovoid to fusiform, 2.5–3 mm, apex acuminate; fertile scales ovate, 1.5 mm, apex acute, midrib shortexcurrent. Flowers: perianth absent. Fruits 0.9–1 mm; body lustrous pale-brown, ellipsoidlenticular, 0.8–0.9 × 0.5–0.6 mm, margins narrow, wirelike; surfaces minutely reticulate; bristles 4–6, the longest from shorter than fruit midbody to fully as long, rarely reaching tubercle tip, minutely antrorsely barbellate; tubercle shortconic, to 0.15 mm.


Phenology: Fruiting late spring summer.
Habitat: Fluctuating shores of limesink ponds, seeps over calcareous rock
Elevation: 0–200 m

Discussion

Of conservation concern.

Rhynchospora thornei, discovered by Robert Thorne from margins of a limesink pond in southwestern Georgia, has been extirpated at that site. Now the taxon is known from several Alabama and Florida locations and was recently found in eastern North Carolina by R. J. LeBlond.

Had S. Gale been sent material of Rhynchospora thornei at the time she was doing her excellent revision, she probably would have treated it as part of her series Rariflorae. Yet without its perianth bristles, R. thornei would be nearly identical to R. divergens and very similar to R. pusilla, both of which belong in subg. Psilocarya. Therefore, it forms an interesting link between subg. Rhynchospora (Eurhynchospora sensu Gale) and subg. Psilocarya.

Selected References

None.

Lower Taxa

None.

"shortened" is not a number."longest" is not a number."wider" is not a number.

... more about "Rhynchospora thornei"
acute;acuminate;setaceous;tapering;trigonous +
Robert Kral +
2-lobed +  and lunate +
scabridulous +  and scabrid +
v--shaped +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
pale-brown +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.09 cm0.9 mm <br />9.0e-4 m <br />) +
warty +, papillate +, alveolate +  and pitted +
ridged +, terete +, lenticular +  and flattened +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
2-ranked +  and arranged +
ascending +  and appressed +
setaceous +
parallel +  and divergent +
terete +, rolled +  and plicate +
filiform +
Ala. +, Fla. +, Ga. +  and N.C. +
0–200 m +
distalmost +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
biconvex +  and trigonous +
Fluctuating shores of limesink ponds, seeps over calcareous rock +
spaced +  and cluster +
erect +, rarely +  and spreading +
3-ranked +  and polystichous +
spreading;ascending +
cauline +  and basal +
exceeded by culm +  and exceeding +
wirelike;channeled;involute +
revolute +  and involute +
decurrent +
plumed +  and barbed +
deciduous +  and persistent +
shorter or longer +
of 2-12(-20) bristles +
Fruiting late spring summer. +
2-3(-4)-carpellate +
3 (?) +  and 1 (?) +
adventitious +
basal +  and proximal +
1.5 cm15 mm <br />0.015 m <br /> (?) +
cylindric +
Illustrated +, Endemic +  and Conservation concern +
1 +, 3 +  and 100 +
lanceovoid;fusiform +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
2 +  and 3 +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
cleft +, 2-fid +  and undivided +
Dichromena +  and Psilocarya +
Rhynchospora thornei +
Rhynchospora +
species +
sulcate +  and 2-edged +
flattened +, terete +, triangular +  and conic +
0 cm0 mm <br />0 m <br /> (0.015 cm0.15 mm <br />1.5e-4 m <br />) +
plant +  and cespitose +