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

PASPALUM/POACEAE
1019
loam soils; widespread in the s part of East TX and Cass Co. (Turner et al. 2003) to the n; also
Gulf Prairies and Marshes, South TX Plains, and e Edwards Plateau; se U.S. from SC s to FL w to
TX. Mar–Nov. [P. texanum Swallen]
Paspalum praecox Walter, (appearing or developing early), EARLY PASPALUM, EARLY CROWN
GRASS. Perennial with short rhizomes; culms 50–100(–160) cm tall; ligule 1–2.5 mm long; inflorescence
branches usually 3–6(–10), 2–7(–10) cm long, the branch axes only slightly winged;
spikelets 2.2–3.3 mm long, paired or both solitary and paired on either side of branch axis;
lower glume absent; upper glume and lemma of sterile floret glabrous. Bogs, wet savannahs,
other wet habitats; Freestone, Hardin, Jasper, Tyler (BRIT), Liberty, Sabine (SBSC), Anderson,
Angelina, Gonzales, Harris, and Jefferson (Turner et al. 2003) cos., mainly se part of East TX,
disjunct sw to Gonzales Co. (Turner et al. 2003); also n Gulf Prairies and Marshes; se U.S. from
VA s to FL w to AR and TX, also IL. May–Oct. [P. lentiferum Lam., P. praecox var. curtissianum
(Steud.) Vasey]
Paspalum pubiflorum Rupr., (hairy-flowered), HAIRY-SEED CROWN GRASS, HAIRY-SEED PASPALUM.
Tufted perennial without rhizomes; culms decumbent below, often rooting at the lower nodes,
usually 40–80(–130) cm tall; leaf sheaths glabrous or the lower pilose; ligule 1–3.2 mm long; leaf
blades with margins often crisped; inflorescence branches (2–)3–7(–10), usually 3–10 cm long,
the branch axes winged, sometimes rather broadly; spikelets 2.6–3.6 mm long, mostly paired, in
4 rows, glabrous or pubescent; lower glume absent. Ditches and other moist areas; the map in
Turner et al. (2003) and the one presented here do not distinguish varieties; e U.S. from PA s to
FL w to CO and TX. Mainly May–Nov. While some authorities (e.g., Allen 1992; Kartesz 1999;
Allen & Hall 2003) do not recognize infraspecific taxa, we are following Gould (1975b), Jones et
al. (1997), and Hatch (2002) in recognizing 2 varieties in this species. However, if additional
characters are not found, the usefulness of recognizing varieties solely on the basis of spikelet
pubescence is questionable.
1. Spikelets glabrous _______________________________________________________________ var. glabrum
1. Spikelets pubescent ____________________________________________________________ var. pubiflorum
var. glabrum Vasey ex Scribn., (smooth, without hairs), SMOOTH-SEED PASPALUM. Dallas, Delta,
Fannin, Grayson, Hunt (BRIT), Harris, and Rockwall (Gould 1975b) cos.; scattered in the e 1/2 of
TX, but less frequent than var. pubiflorum (Gould 1975b).
var. pubiflorum, HAIRY-SEED PASPALUM, HAIRY-FLOWER PASPALUM. Widespread in TX except the
nw part of the state.
Paspalum repens P.J. Bergius, (creeping), WATER PASPALUM, HORSE-TAIL CROWN GRASS, HORSE-TAIL
PASPALUM. Mat- or tuft-forming creeping annual (perennial in tropical America) of wet habitats,
the culms often floating; decumbent culms to 1(–2) m long, the flowering culms to ca. 60 cm
tall; ligule 1–2(–4) mm long; inflorescence with branches usually numerous (8–65+), these
eventually falling from the main axis, usually (2–)3–7(–9.5) cm long, the branch axes broadly
winged, almost leaf-like, extending beyond the most distal spikelet as a pointed tip, as wide or
wider than the rows of spikelets, the wing margins sometimes even slightly wrapping around
the spikelets; spikelets 1.2–1.7(–2) mm long, solitary, in 2 rows; lower glume absent; upper glume
and lemma of lower floret puberulent. Wet areas of ditches, marshes, edges of lakes and
streams; s Pineywoods and adjacent Post Oak Savannah; also reported by Gould (1975b) and
Hatch et al. (1990, 1999) for Gulf Prairies and Marshes; e U.S. from MD s to FL w to KS and TX.
Mostly late summer–fall. [P. f luitans (Elliott) Kunth, P. mucronatum Muhl., P. repens var. fluitans
(Elliott) Wipff & S.D. Jones] The TX members of this species have long gone under the name of
P. f luitans (e.g., Correll & Johnston 1970; Gould 1975b; Hatch et al. 1990; Kartesz 1999). Jones and
Wipff (1994 [1995]) treated the temperate members as P. repens var. fluitans. However, Morrone
et al. (1996), in the most recent revision of the group, combined both the temperate (P. fluitans)