Plants with short, knotty rhizomes. Culms 1-2(4) m tall, 3-5 mm
thick, clumped. Sheaths usually glabrous, occasionally slightly pilose;
ligules ciliate; blades 30-75(120) cm long, 9-35(45) mm wide,
flat, usually glabrous, tapering to attenuate apices. Terminal inflorescences
erect, with (1)2-3(6) rames; rames 12-25 cm. Pistillate spikelets
6-8 mm long, 3-5.5 mm wide. Staminate spikelets all sessile or subsessile;
glumes 5-12 mm, coriaceous, blunt, acute, or bifid; pedicels,
when present, about 1 mm long, 0.5-0.8 mm wide, triangular in cross section,
rigid. 2n = 36, 54, 72.
Tripsacum dactyloides grows in water courses and limestone outcrops
from the central and eastern United States through Mexico to northern
South America. Plants from the United States and northern Mexico belong
to Tripsacum dactyloides (L.) L. var. dactyloides. They
differ from those of the other two varieties in their erect stems and
sessile staminate spikelets. Narrow-bladed plants of T. dactyloides from
Texas resemble
T. floridanum, but on transplanting
to favorable conditions develop the wider blades characteristic of T.
dactyloides.
The two species can hybridize; the hybrids are partially sterile.
Growing Tripsacum dactyloides for forage has proven
practical only in South America. It is also used as an ornamental grass, the
chief attraction being its foliage.
Plants with short, thick rhizomes. Culms to 1 m tall, to 2 mm thick,
usually solitary or in small clumps. Sheaths glabrous; blades to
60 cm long, 1-7(15) mm wide, involute or folded, glabrous. Terminal inflorescences
erect, with 1-2 rames. Pistillate spikelets 3.5-4.5 mm wide. Staminate
spikelets sessile-pedicellate; spikelets 5-7 mm; glumes coriaceous,
acute; pedicels to 2 mm long, to 0.5 mm wide, triangular in cross section.
2n = 36.
Tripsacum floridanum grows along roadsides and in pine woods, often in
wet soils, of Florida and Cuba. It is grown as an ornamental, but it reseeds rather
too readily under some conditions. Reports of T. floridanum from Texas
are based on narrow-bladed specimens of T.
dactyloides.
Culms 1-3 m, in large clumps from thick rhizomes; blades elongate, often to 2 cm wide; spikes 1-4, 10-25 cm, the lower fourth or third pistillate; spikelets 7-10 mm; first glume of the pistillate spikelets toward the outside of the pit, indurate, ovate, acute; both staminate spikelets of a pair sessile or subsessile, the outer glumes oblong; 2n=18,
36, 45, 54, 72, 90, 108. Swamps and wet soil; trop. Amer., n. in e. and c. U.S. to Mass., s. Mich. (only casual), Io., and Nebr.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.