keys to the vascular plants of east texas - Botanical Research ...

626 CYPERACEAE/RHYNCHOSPORA
base. Flatwood ponds (seasonally inundated depressions) within longleaf pine savannahs;
Anderson, Hardin, Jasper, and Newton (BRIT) cos., typically on the Beaumont and Lissie geologic
formations (Bridges & Orzell 1989a); mainly se U.S. from NJ s to FL w to TX, also NY. Aug–
Nov. [R. cephalantha var. attenuata Gale] First reported in the literature for TX in 1989 (Bridges
& Orzell 1989a).
Rhynchospora chalarocephala Fernald & Gale, (loose head), LOOSE-HEAD BEAK SEDGE. Tufted
perennial to 1 m tall; inflorescences with spikelets usually in loose turbinate or hemispheric
clusters; spikelets 3–5.5 mm long; achenes 1.4–1.7(–2) mm long, oblong-obovoid, lenticular; tubercle
1–1.6(–2) mm long. Hillside seepage bogs, typically on the Carrizo, Queen City,
Catahoula, Willis, and Lissie geologic formations (Bridges & Orzell 1989a); Anderson, Angelina,
Freestone, Henderson, Jasper, Newton (BRIT), Leon (Bridges & Orzell 1989a), Sabine, San Augustine,
and Wood (Turner et al. 2003) cos.; se U.S. from NJ s to FL w to OK and TX. (Late Jun–)
Aug–Sep(–Oct). First reported for TX in 1989 (Bridges & Orzell 1989a), but collected by
Shinners as early as 1954 (Shinners 19019, Freestone Co.—BRIT).
Rhynchospora colorata (L.) H. Pfeiff., (colored), WHITE-TOP UMBRELLA-GRASS, STAR-RUSH WHITE-
TOP SEDGE, UMBRELLA-GRASS, STAR-RUSH WHITE-TOP, NARROW-LEAF WHITE-TOP. Rhizomatous perennial
to ca. 56(–70) cm tall; leaves cauline although sometimes crowded near base; inflorescence
a hemispherical to globose head; bracts unequal in length, the longer ones (2.5–)5–13(–18)
cm long; white zone on bracts conspicuous, (0.25–)0.5–2(–2.5) cm long; spikelets (3–)5–7(–8)
mm long, with white scales; achenes ca. 1 mm long, broadly obovoid, tumidly lenticular. Open,
often disturbed sites including pastures, roadsides, and savannahs, in sandy, neutral or slightly
basic soils; widespread in s half of e TX n to Angelina and Leon (Turner et al. 2003) cos.; also
Gulf Prairies and Marshes and Edwards Plateau.; se U.S. from VA s to FL w to AR and TX.
(Spring–)Summer. Previously separated into the genus Dichromena [as D. colorata (L.) Hitchc.].
m/296
Rhynchospora corniculata (Lam.) A. Gray, (horned), HORNED BEAK-RUSH, HORNED-RUSH, SHORT-
BRISTLE HORNED BEAK-RUSH. Coarse tufted perennial 0.5–1.5(–2) m tall, similar to R.
macrostachya; culms sharply triangular; inflorescence large, with spreading branches; spikelets
strikingly elongate (15–26 mm long including exserted tubercle), usually in clusters of 3–7(–14);
bristles 3–6, but normally 5, unequal, ca. 2–5 mm long; achenes 3.5–5(–6) mm long, 2–3.5 mm
wide, oblong-ellipsoid, the faces flattened, the margins thickened, often crimped; tubercle extremely
conspicuous, long-subulate, 10–20 mm long. Mud, edge of ponds, or on decaying logs
in water; widespread in e 1/3 of TX; e U.S. from DE s to FL w to IL and TX. Spring–Summer
(fruit present into fall). [R. corniculata var. interior Fernald] m/296
Rhynchospora debilis Gale, (weak, frail), SAVANNAH BEAK SEDGE. Delicate tufted perennial 50 cm
or less tall, similar to R. fascicularis but shorter and less coarse; inflorescence usually of a single
terminal cluster, rarely with 1–2 lateral clusters; spikelets 2–3.2 mm long; achenes 1.3–1.5 mm
long, broadly obovoid to � orbicular, lenticular; tubercle 0.3–0.4 mm long. Moist open areas,
sandy or sandy peat soils; Hardin Co. (Turner et al. 2003); also Chambers Co. (Turner et al. 2003)
in n Gulf Prairies and Marshes; se U.S. from VA s to FL w to TX. May–Oct. [R. trichodes of authors,
not C.B. Clarke] In the se U.S., this species is a “common invader of cutover and bulldozed
low pineland where it assumes a low-spreading habit, its many culms radiating from the common
center like spokes in a wheel ” (Kral 2002c). While not officially designated as such (e.g.,
TOES 1993; Carr 2002d; Poole et al. 2002), given its limited distribution in the state, we consider
this species to be of conservation concern in TX. �
Rhynchospora divergens Chapm. ex M.A. Curtis, (wide-spreading), SPREADING BEAK SEDGE.
Tufted perennial 60 cm or less tall, similar to R. pusilla but differing in texture of achenes (see
key to species); spikelets 2–2.5(–3) mm long; perianth bristles absent; achenes 0.6–0.7 mm long,