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

1074 POACEAE/SPOROBOLUS
Sporobolus junceus (P. Beauv.) Kunth, (rush-like, resembling Juncus—rush), PINEYWOODS
DROPSEED, PURPLE DROPSEED, WIRE GRASS. Perennial; culms usually 50–100 cm tall; panicles usually
10–28 cm long; spikelets 3–3.8 mm long. Pine and hardwood forests, sandy prairies, usually
sandy to loamy soils; Pineywoods and Post Oak Savannah, also Gulf Prairies and Marshes and n
South TX Plains; se U.S. from VA s to FL w to AR and TX, also AZ. (Spring), mostly Sep–Nov. [S.
gracilis (Trin.) Merr.]
Sporobolus neglectus Nash, (overlooked), PUFF-SHEATH DROPSEED, SMALL DROPSEED, POVERTY
GRASS. Annual similar to S. vaginiflorus; culms 10–40 cm long, erect or decumbent; leaf sheaths
mostly glabrous but with some hairs at apex, somewhat inflated; panicles contracted, 2–5 cm
long, often only apical portion exserted from subtending sheaths, the axillary panicles shorter,
almost entirely enclosed by sheaths; spikelets (1.3–)1.6–2.8 mm long; lemma white or purpletinged,
glabrous. Disturbed sites; Grayson Co. (BRIT) near nw margin of East TX; also Cross
Timbers and Prairies (Bosque and Mills cos.—BRIT) and Edwards Plateau (Hatch et al. 1990;
Hatch 2002); s Canada and widespread in much of the U.S. Aug–Nov. Jones et al. (1997) treated
this species as S. vaginiflorus (Torr. ex A. Gray) A.W. Wood var. neglectus (Nash) Scribn. According
to Yatskievych (1999), this species is sometimes difficult to separate from the closely related
S. ozarkanus and S. vaginiflorus. Peterson et al. (2003) noted, “Sporobolus vaginiflorus is very
similar to S. neglectus, but it differs in having strigose lemmas, sheaths that are sparsely hairy
toward the base and, usually, longer spikelets.” Sporobolus neglectus is unusual in that “when
the fruits become wet, the outer coat [pericarp] swells slightly and becomes somewhat sticky or
gelatinous, as opposed to merely becoming loosened from the seed (and often releasing it)”
(Yatskievych 1999). While not officially designated as such (e.g., TOES 1993; Carr 2002d; Poole
et al. 2002), given its limited distribution in the state, we consider this species to be of conservation
concern in TX. �
Sporobolus ozarkanus Fernald, (of the Ozarks), OZARK DROPSEED, OZARK POVERTY GRASS. Annual
similar to S. vaginiflorus but differing as in the key and with all reproductive parts averaging
smaller; culms 4–50(–60) cm tall; panicles 2–5 cm long; spikelets (1.9–)2.3–3.8(–4.2) mm
long; lemma 2.1–3.5(–3.9). Limestone areas, roadsides; Grayson (BRIT), Grimes (TAMU) and San
Jacinto (E. Keith 20A, BRIT) cos.; also cited for s part of Blackland Prairie (Gould 1975b) and
Cross Timbers and Prairies and Edwards Plateau by Hatch et al. (1990); e U.S. from VA s to FL w
to KS and TX. Aug–Oct. [S. neglectus Nash var. ozarkanus (Fernald) Steyerm. & C. Kucera, S.
vaginiflorus (Torr. ex A. Gray) A.W. Wood var. ozarkanus (Fernald) Shinners] Jones et al. (1997)
treated this taxon within S. vaginiflorus var. neglectus, while Kartesz (1999), Hatch (2002), and
Peterson et al. (2003) recognized it as S. vaginiflorus var. ozarkanus. It differs from S.
vaginiflorus in a number of characters, and until a detailed study is done of this and related
taxa (e.g., S. neglectus), we are following Riggins (1969) and Yatskievych (1999) in recognizing it
at the specific level. However, some individuals of S. ozarkanus and S. vaginiflorus are difficult
to distinguish (Yatskievych 1999). While not officially designated as such (e.g., TOES 1993; Carr
2002d; Poole et al. 2002), given its limited distribution in the state, we consider this species to be
of conservation concern in TX. �
Sporobolus purpurascens (Sw.) Hamilton, (purplish or turning purple), PURPLE DROPSEED. Perennial;
culms 25–95 cm tall; panicles (7–)10–25(–30) cm long, the branches short, in well-spaced
and -defined whorls giving the inflorescence a distinctive interrupted appearance; spikelets 3–
4.5 mm long. Prairies, brushy areas, sandy soils; Bexar Co. (Turner et al. 2003) near sw margin of
East TX; otherwise s Gulf Prairies and Marshes and s South TX Plains; in the U.S. known only
from TX; also Latin America. (Spring), but mostly Oct–Nov. [Agrostis purpurascens Sw.] According
to Gould (1975b), this species is closely related to S. junceus. It can be distinguished by the
narrower panicles 1.6 cm or less wide, with short branches 0.8–1.5(–2) cm long, these bearing
flowers to the base or nearly so, versus S. junceus with the panicles 3–6 cm wide with branches
2–3.5 cm long, these naked on ca. the lower half.