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

1060 POACEAE/SORGHASTRUM
1. Margins of uppermost leaf sheaths glabrous; leaf blades strigose on the abaxial (lower) surfaces;
distribution primarily subtropical ____________________________________________________ S. adhaerans
1. Margins of uppermost leaf sheaths ciliate; leaf blades scabrous on the abaxial surfaces; distribution
primarily temperate ___________________________________________________________ S. verticillata
Setaria villosissima (Scribn. & Merr.) K. Schum., (very villous, very soft hairy), HAIRY-LEAF
BRISTLE GRASS. Tufted perennial 50–100 cm tall; leaf blades � densely villous on both upper and
lower surfaces; panicle usually 8–20 cm long; bristles mostly 12–25 mm long; spikelets 2.8–3.4
mm long; lemma of fertile floret finely but conspicuously rugose. Primarily on soils derived
from granitic rocks; Anderson Co. (Turner et al. 2003)—if correctly identified, this is a surprising
eastward disjunction since the species is primarily found in the Edwards Plateau and Trans-
Pecos; Hatch (2002) cited only vegetational areas 6, 7, and 10; AZ and TX. Summer–fall.
[Chaetochloa villosissima Scribn. & Merr.]
Setaria viridis (L.) P. Beauv., (green), GREEN BRISTLE GRASS, GREEN FOXTAIL GRASS. Annual to 100
cm tall; leaf sheaths slightly compressed; leaf blades mostly 3–10(–15) mm wide, glabrous or
scabrous; panicle rather soft and flexible, erect or nodding from the tip but not from the base;
bristles usually green; spikelets 1.6–2.6 mm long; lemma of fertile floret finely rugose. Disturbed
sites; widely scattered in TX. May–Oct. Native of Eurasia. This species is sometimes treated as a
subspecies of the cultivated S. italica as [S. italica (L.) P. Beauv. subsp. viridis (L.) Thell.] Some
authorities (e.g., Rominger 1962; Jones et al. 1997; Kartesz 1999; Yatskievych 1999; Rominger
2003) recognize 2 varieties in S. viridis; all East TX material that we have seen falls into var.
viridis. The following key to varieties is modified from Rominger (1962, 2003) and Yatskievych
(1999). � I
1. Flowering culms (100–)150–250 cm long; leaf blades 15–40 cm long, 10–25 mm wide; inflorescences
8–20 cm long ________________________________________________________________ var. major
1. Flowering culms to 100(–140) cm long; leaf blades 4–25 cm long, 3–10(–15) mm wide; inflorescences
3–10(–15) cm long ___________________________________________________________ var. viridis
var. major (Gaudin) Peterm., (bigger, larger). Reported for TX (Kartesz 1999), but no definitive
specimens seen; included here as note for clarification but not considered a member of the East
TX flora; IL, MI, NJ, PA, TN, TX, and WI. Native of Europe. This is a robust form of the species.
The longer inflorescences are reported to have a greater tendency to droop in their upper half
(Yatskievych 1999). I
var. viridis. Widely scattered in TX; throughout most of Canada and the U.S. Native of Eurasia.
A weed in crop fields; considered noxious in CO (Kartesz 1999). Rominger (1962) indicated that
this is a cosmopolitan weed that is “undoubtedly an inhabitant of every province of Canada
and state of the United States.” � I
SORGHASTRUM Nash INDIAN GRASS
Coarse perennials; leaves mostly cauline; ligule a ciliate membrane; leaf blades flat, often conspicuously
bluish green; inflorescence a long-exserted panicle, sometimes nodding; spikelets in
pairs, one sessile and fertile, the other pedicelled and vestigial or absent (in ours reduced to only a
hairy pedicel ca. as long as the fertile spikelet, the spikelet lacking); disarticulation so that associated
pedicel and section of the inflorescence branch fall with sessile spikelet; terminal spikelet
of a branch flanked by two pedicels; glumes subequal; fertile spikelet 2-flowered, the lower
floret reduced or absent; lemma of the upper, fertile floret with a geniculate and twisted awn.
AA genus of 17 species (Dávila Aranda & Hatch 2003) of tropical and warm areas of the
Americas and Africa, typically characterized by having the pedicellate spikelet reduced to a
pedicel only. Like all members of the Andropogoneae, it is characterized by C4 photosynthesis