Rhynchospora latifolia
Rhynchospora filifolia
sandswamp whitetop
threadleaf beaksedge
arching or erect, leafy-based, distally wandlike, terete, multiribbed.
erect or excurved, mostly filiform, leafy proximal to midculm, obtuse-angled to subterete, wiry.
ascending to spreading, overtopped by scape;
blades linear, proximally flat, 2.5–5 mm wide, apex subulate, trigonous.
overtopped by culm;
blades narrowly linear, proximally flat, 1–2 mm wide, distally tapering-triquetrous.
terminal, headlike clusters of spikelets, clusters dense, leafy-involucrate;
involucral bracts several, spreading to downcurved, longest 6–13 cm × 5–10 mm, mostly white to midbract, then green, abruptly narrowly linear.
spikelet clusters 2–3(–4), distant, narrowly turbinate to hemispheric, mostly shorter than subtending setaceous bract.
white, ovoid, 5–7 mm;
fertile scales boatshaped, sharply curved-keeled, 5 mm, apex acute.
red-brown, lanceoloid, 2.5–3(–4) mm, apex acuminate;
fertile scale elliptic, 2–2.5 mm, acute, midrib excurrent as cusp or aristula.
perianth absent.
bristles 6, reaching tubercle tip or beyond, antrorsely barbellate, base setose.
several per spikelet, 1.5–2 mm;
body yellowish to deep brown, tumidly lenticular, broadly obovoid to orbicular or oblate, 1.5 mm, widest at or toward midbody, margins flowing to tubercle;
surfaces with many fine rows of vertical shallow lattices, their contiguous ends making transverse rows of papillae;
tubercle crescent-based, depressed-triangular, 0.5 mm, apex acute.
2–4 per spikelet, 1.5–1.7 mm, on setose pedicellar joint 0.2 mm, body with faces red-brown with pale glassy center, decurrent tubercle base;
surfaces smooth;
turbercle concavely triangular, 0.4–0.6 mm, setulose-ciliate.
= 12.
Rhynchospora latifolia
Rhynchospora filifolia
A specimen collected near Tullahoma, Tennessee, reported as Dichromena latifolia (A. Gattinger 1901), was later destroyed by fire. I did not see the specimen, nor was a description of it published. Because extant populations of the similar Rhynchospora colorata are just over the border in Alabama, that species is likely to have been the one found by Gattinger.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
On the acidic, sphagnous substrates shaded by Taxodium ascendens, Nyssa biflora, and Ilex myrtifolia stands in western Florida and southern Alabama, culms of Rhynchospora filifolia reach their greatest length and are lax, leaning on other vegetation, and produce increasingly more distant clusters of spikelets that are of a paler color than is usual for the species. In fact, R. filifolia presents the greatest morphologic spectrum for its complex of species, a complex best held together by the uniformity of its fruits.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
LA Plants
WildflowerSearch
iNaturalist
USDA Plants Database
MD Biodiversity
