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

616 CYPERACEAE/KYLLINGA
REFERENCES: Beetle 1947; Johnston 1964a; Tucker 1987; Bruhl 1995; Smith 1995, 2002c; Smith &
Yatskievych 1996; Muasya et al. 2000b, 2001; Muasya & Simpson 2002.
1. Scales of spikelets neither gibbous nor clasping shed achenes, usually at least partly orangebrown
to red-brown or blackish; achenes compressed-trigonous or thickly plano-convex; leaf
sheaths usually reddish near base; anthers 0.3–0.6 mm long; species primarily near coast __________ I. cernua
1. Scales of spikelets markedly gibbous (= swollen basally on one side), often clasping shed achenes,
colorless to stramineous or orangish or greenish; achenes equilaterally trigonous; leaf sheaths
green to stramineous or brown; anthers ca. 0.2 mm long; species widespread in East TX.
2. Scales from middle of spikelet 1.8–2 mm long, short-awned (awns 0.2–0.5 mm long); achenes
(1–)1.3–1.6 mm long _____________________________________________________________ I. carinata
2. Scales from middle of spikelet 1–1.2(–1.5) mm long, mucronate (the mucros 0.1 mm or less
long); achenes 0.7–1 mm long _______________________________________________ I. pseudosetacea
Isolepis carinata Hook. & Arn. ex Torr., (with a keel), ANNUAL BULRUSH, KEELED BULRUSH, KEELED
LATERAL BULRUSH. Tufted annual 4–25(–30) cm tall; leaf blades 0.2–0.5 mm wide; involucral
bract 5–30 mm long; spikelets usually solitary, sometimes 2(–3), 2–10 mm long, 1.5–2 mm wide;
scales of spikelet strongly keeled. Moist sandy soils; widespread in East TX w to e Cross Timbers
and Prairies and e Edwards Plateau; also n Gulf Prairies and Marshes; se 1/4 of U.S. from
NC and FL w to KS and TX, also CA. Spring. [I. koilolepis Steud., Scirpus koilolepis (Steud.)
Gleason, Scirpus carinatus (Hook. & Arn. ex Torr.) A. Gray, not Sm.]
Isolepis cernua (Vahl) Roem. & Schult., (drooping, nodding), LOW LATERAL BULRUSH. Tufted annual
(perennial?) 4–40 cm tall; leaf blades 0.2–1 mm wide; involucral bract 2–6(–23) mm long;
spikelet usually solitary, 2–5 mm long, 1–2 mm wide; scales of spikelet keeled near tip; achenes
often with a white waxy coating. Moist sandy soils; Harris and Jefferson (Turner et al. 2003) cos.
near boundary of Pineywoods and Gulf Prairies and Marshes; known in TX from only 2 counties;
Pacific Coast and TX. Spring–fall. [Scirpus cernuus Vahl, Scirpus cernuus subsp.
californicus (Torr.) Thorne, Scirpus cernuus var. californicus (Torr.) Beetle] According to Smith
(2002c), this species was first collected in TX in 1974. 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. �
Isolepis pseudosetacea (Daveau) Laine, (false bristled), GULF COAST LATERAL BULRUSH. Tufted
annual 2–20 cm tall; involucral bract 3–10(–25) mm long; spikelets 1–3, 2–8 mm long, 1–1.5 mm
wide; scales of spikelet keeled. Moist sandy soils; Jasper, Montgomery, Rusk, Sabine (BRIT), Austin,
Bastrop, Brazos, Madison, Tyler, and Walker (Turner et al. 2003) cos.; also n Gulf Prairies and
Marshes; se U.S. from GA w to MO and TX. Spring–summer. [Isolepis molesta (M.C. Johnst.) S.G.
Sm., Scirpus molestus M.C. Johnst., Scirpus pseudosetaceus Daveau (as pseudo-setaceus)]
Johnston (1964a) indicated that while this species (as S. molestus) seems like a dwarf form of I.
carinata, clear-cut differences exist and no intermediate specimens are known. The two species
often grow intermixed (Yatskievych 1999; Smith 2002c), and this taxon should be looked for in
mixed populations. While this species has long gone under the epithet molestus/molesta in either
Scirpus or Isolepis, we are following Muasya and Simpson (2002) and Smith (2002c) in recognizing
the older epithet pseudosetacea.
KYLLINGA Rottb. SPIKE SEDGE, GREEN-HEAD SEDGE
Small rhizomatous or tufted annuals or perennials to 40(–55) cm tall; inflorescence a single,
cylindrical to ovoid or roundish, unlobed to 3-lobed, congested head or head-like mass, (3–)4–
12(–17) mm long, subtended by usually 3–4 involucral bracts; spikelets flat, 1.8–4 mm long,
each with only a single, fertile, bisexual flower and only 4 scales, 2 of these normal in size, the
basal 2 minute, brownish, the scales 2-ranked; spiklets each deciduous as a unit; styles 2branched;
achene 1 per spikelet, lenticular, without a tubercle.