17.38   TRICHLORIS E. Fourn. ex Benth.
Mary E. Barkworth

Plants perennial; cespitose, sometimes stoloniferous. Culms to 150 cm, herbaceous, solid, glabrous. Sheaths open, rounded; ligules membranous, ciliate, cilia longer than the membranous base, conspicuous tufts of stiff hairs present on either side of the ligules; blades linear, flat or folded. Inflorescences terminal, panicles of non-disarticulating spikelike branches, exceeding the leaves; branches in 1 or more whorl(s), spikelets in 2 rows on the abaxial side of the branches, axes terminating in a functional spikelet. Spikelets laterally compressed, with 2-5 florets, lowest 1-2 florets bisexual, distal 1-3 florets progressively reduced and sterile; disarticulation above the glumes, all the florets falling as a unit. Glumes much shorter than the spikelets, membranous; lower glumes linear, acuminate; upper glumeslanceolate-ovate, awned; calluses bearded; lowest lemmas linear-lanceolate, 3-veined, veins prolonged into 3 awns; central awns 8-12 mm; lateral awns 0.5-12 mm; paleas 2-keeled, acute; distal floret(s) 1-3-awned; lodicules 2; anthers 2 or 3. Caryopses sulcate; embryos 1/2 as long as the caryopses; hila punctate. x = 10. Name from the Latin tri, three, and the genus Chloris, referring to the 3-awned lemmas and the resemblance to Chloris.

Trichloris has two species, both of which are native to the Flora region. It differs from Chloris in its 3-awned lemmas. Both species of Trichloris have a disjunct distribution, populations in North America being widely separated from those in South America.


SELECTED REFERENCE Davidse, G. 1994. Trichloris E. Fourn. ex Bentham. P. 289 in G. Davidse, M. Sousa S., and A.O. Chater (eds.). Flora Mesoamericana, vol. 6: Alismataceae a Cyperaceae. Universidad Nacional Autónoma de México, Instituto de Biología, México, D.F., México. 543 pp.

1
Lowest lemma awns subequal, the central awns 8-12 mm long, equaling or slightly longer than the lateral awns ..... 1. T. crinita
Lowest lemma awns unequal, the central awns 8-12 mm long, the lateral awns 0.5-1.5 mm long ..... 2. T. pluriflora


1.   Trichloris crinita (Lag.) Parodi
False Rhodesgrass

Plants perennial; cespitose, sometimes stoloniferous. Culms to 100 cm. Sheaths glabrous or sparsely hirsute; ligules to 3 mm; blades to 20 cm long, 5-10 mm wide, scabrous. Panicles with 6-20 branches in several closely-spaced whorls, appearing as a single terminal cluster; branches to 15 cm, erect, with 7-9 spikelets per cm. Spikelets with 1 bisexual and 1(2) sterile floret(s). Lower glumes 0.8-1.1 mm; upper glumes 2-2.5 mm, awned, awns to 2 mm; lowest lemmas 2.4-3.8 mm long, about 0.5 mm wide, dorsally compressed, narrowly lanceolate to elliptic, scabrous, particularly distally, apices bilobed and 3-awned, central awns 8-12 mm, equaling or slightly longer than the 5-12 mm lateral awns; first sterile florets 1-1.5 mm, narrowing to 3 subequal 5-7 mm awns; second sterile florets, if present, similar but smaller. Caryopses 1.7-2.3 mm, strongly dorsally flattened. 2n = 40.

Trichloris crinita is a native species that grows in the southwestern United States and northern Mexico, and, as a disjunct, in northern Argentina.


2.   Trichloris pluriflora E. Fourn.
Multiflower False Rhodesgrass

Plants perennial; stoloniferous or cespitose. Culms to 150 cm. Sheaths glabrous or sparsely hirsute; ligules to 3 mm; blades to 30 cm long, to 10 mm wide, scabrous or sparsely hirsute. Panicles with 7-20 branches in a few, evidently separate whorls; branches to 20 cm, ascending, with 7-9 spikelets per cm. Spikelets with 1-2 bisexual florets, a third floret with a rudimentary pistil and stamens sometimes present below the (1)2-3 sterile florets. Lower glumes 2-3 mm; upper glumes 3-5 mm; lowest lemmas 3-5 mm, mostly glabrous, margins short-ciliate near the middle, sparsely scabrous distally, apices 3-awned, central awns 8-12 mm, lateral awns 0.5-1.5 mm; lowest sterile florets 1.5-3 mm long, about 0.3 mm wide, mostly glabrous, margins sometimes short-ciliate near the middle, apices 3-awned, central awns to 8 mm, lateral awns 0.2-1 mm. Caryopses 1.8-2.2 mm, strongly dorsally compressed. 2n = 80.

Trichloris pluriflora is native from southern Texas to Guatemala and, as a disjunct, from Ecuador to Argentina.