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

TRICHONEURA/POACEAE
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guish it from Chloris. According to Barkworth (2003d), both species “have a disjunct distribution,
populations in North America being widely separated from those in South America.”
(Latin: tri, three, and the genus Chloris, windmill grass, in reference to the 3-awned lemmas
and the resemblance to Chloris) (subfamily Chloridoideae, tribe Cynodonteae)
REFERENCES: Hilu & Alice 2001; Barkworth 2003d.
Trichloris pluriflora E. Fourn., (many-flowered), MULTI-FLOWERED FALSE RHODES GRASS. Perennial,
often stoloniferous; culms to 1.5 m tall; ligule to 3 mm long; leaf blades 10 mm or less wide; inflorescence
a panicle with 7–20 branches in whorls, the branches to 20 cm long; spikelets with 2–6
florets, the lowest 1–2 florets bisexual, the distal ones reduced and sterile, disarticulating above
the glumes, all florets falling as a unit; glumes 2–5 mm long, the upper one longer; lemmas of
lower florets 3–5 mm long, apically 3-awned, the lateral awns 1.5 mm or less long, the middle awn
much longer, 8–12 mm long. Low brushy areas; Bexar and Fannin (TAES) cos. (the Fannin County
collection is well out of normal range and is likely the result of mistaken label data—it is not
mapped on the county distribution map); mainly Gulf Prairies and Marshes and South TX Plains.
Summer. [Chloris pluriflora (E. Fourn.) Clayton] According to Barkworth (2003d), this species is
“native from southern Texas to Guatemala and, as a disjunct, from Ecuador to Argentina.”
TRICHONEURA Andersson SILVEUS’ GRASS
AA C4 genus of 7 species (Wipff 2003b), typically of dry, sandy or rocky soils of tropical Africa,
the Middle East, Texas, n Mexico, Peru, and the Galapagos Islands; only two are native to
the New World. (Greek, thrix, hair, and neuron, nerve, in reference to the ciliate veins of the
lemma) (subfamily Chloridoideae, tribe Cynodonteae)
REFERENCE: Wipff 2003b.
Trichoneura elegans Swallen, (elegant), SILVEUS’ GRASS, HAIRY-NERVE GRASS. Annual 30–115 cm
tall, branching at base, rooting at lower nodes; ligule membranous, 1.5–3 mm long; leaf blades
ca. 2–9 mm wide; inflorescence a panicle usually (5–)7–12(–20) cm long, the numerous unbranched
primary branches erect to ascending-spreading; spikelets on pedicels ca. 1 mm long,
with 5–10 florets, the terminal 1–4 reduced and staminate or sterile, ca. 7–11.5 mm long; disarticulation
above the glumes and between the florets; glumes subequal, acuminate or with a
short awn, the second longer and slightly shorter than to ca. as long as spikelet; lemmas
apically notched, sometimes minutely apiculate, conspicuously ciliate (hairs to 1.6 mm long)
on and adjacent to midsections of lateral veins, the hairs stiff. Fields, prairies, and roadsides,
sandy soils; Bastrop (TAES), Bexar, and Wilson (TEX) cos. in s part of East TX; a Brazos Co. location
mapped by Turner et al. (2003) is based on a cultivated “nursery” specimen (Malone,
TAES); mainly Gulf Prairies and Marshes and South TX Plains; mainly TX, also mapped for AZ
by Wipff (2003h), also n Mexico. (Spring–)late summer–fall.
TRIDENS Roem. & Schult. TRIDENS, FLUFF GRASS
Tufted perennials with erect culms, not rhizomatous or with short rhizomes; ligule a ciliate
membrane; inflorescence a contracted or open panicle; spikelets 3–12-flowered, disarticulating
above glumes and between florets; lower glume 1-veined; lemmas 3-veined, usually with pubescence
on the veins below the middle, rounded on the back, obtuse or acute, usually � 2toothed
or rounded-truncate at apex, the veins often slightly mucronate; stamens 3.
AA C4 genus of 14 species of warm areas of the Americas (e. U.S. to Argentina) (Valdés-Reyna
2003a), excluding Erioneuron and Dasyochloa which have sometimes been included (e.g.,
Hitchcock 1951). It was recognized as the genus Triodia by Hitchcock (1935). (Latin: tri, three,
and dens, tooth, from the 2-toothed lemma tip often with a mucro from between the teeth)
(subfamily Chloridoideae, tribe Cynodonteae)