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

1072 POACEAE/SPOROBOLUS
Sporobolus compositus (Poir.) Merr., (compound), HEAD-LIKE DROPSEED, ROUGH DROPSEED, FLAG
GRASS. Perennial; culms (20–)60–120(–150) cm tall; panicle 5–30 cm long, at least partly included
within leaf sheaths (cleistogamous spikelets often present in axillary panicles); spikelets
4–7.5(–10) mm long. [S. asper (Michx.) Kunth] This species long went under the name S. asper,
but because of nomenclatural considerations, S. compositus is the appropriate binomial
(Kartesz & Gandhi 1995). The map in Turner et al. (2003) and the one presented here do not
separate varieties. According to Peterson et al. (2003), “The Sporobolus compositus complex is a
difficult assemblage of forms, perhaps affected by their primarily autogamous breeding system.”
Sporobolus clandestinus is sometimes recognized as a variety of this species (e.g., Wipff &
Jones 1995); see that species for discussion. However, we are following some recent authors (e.g.,
Peterson et al. 2003) in recognizing only three varieties in S. compositus.
1. Plants with evident short, creeping, scaly rhizomes _______________________________________ var. macer
1. Plants without creeping, scaly rhizomes.
2. Terminal leaf sheaths 0.8–2(–2.5) mm wide when folded naturally (do not spread out to measure);
culms slender, 1–2(–2.5) mm wide near base; primary inflorescence branches 8–18, not
crowded _________________________________________________________________ var. drummondii
2. Terminal leaf sheaths (1.3–)1.5–6 mm wide when folded; culms stout, (1.4–)2–5 mm wide
near base; primary inflorescence branches 12–35, crowded _________________________ var. compositus
var. compositus, TALL DROPSEED, LONG-LEAF RUSH GRASS, ROUGH RUSH GRASS. Cespitose, without
rhizomes. Grasslands, disturbed sites; widespread in e 2/3 of TX; s Canada and widespread in
the U.S., particularly the e 2/3. Sep–Nov.
var. drummondii (Trin.) Kartesz & Gandhi, (for its discoverer, Thomas Drummond, 1780–1835,
Scottish botanist and collector in North America), MEADOW DROPSEED. Cespitose, without rhizomes.
Grasslands, disturbed sites; widespread in e 1/2 of TX; sc U.S. from KY and GA w to IA
and TX. Aug–Nov. [S. asper (Michx.) Kunth var. drummondii (Trin.) Vasey, S. drummondii (Trin.)
Vasey] Jones et al. (1997) included this variety in var. compositus.
var. macer (Trin.) Kartesz & Gandhi, (thin, meager), MISSISSIPPI DROPSEED. Similar to var.
drummondii, but rhizomatous; culms slender, 2(–2.5) mm or less wide; terminal leaf sheath 2.5
mm or less wide when folded. Open woods, margins of woods; Gregg, Titus (BRIT), Anderson,
Bastrop, Brazos, Burleson, Camp, Jasper, and Robertson (TAES—annotated by S. Hatch) cos.; sc
U.S. from MO and MS w to KS and TX. Aug–Nov. [S. asper (Michx.) Kunth var. macer (Trin.)
Shinners, S. macer (Trin.) Hitchc.]
Sporobolus cryptandrus (Torr.) A. Gray, (with hidden flowers), SAND DROPSEED, COVERED-SPIKE
DROPSEED. Perennial; culms 25–100(–120) cm tall; summit of sheaths with tufts of long white
hairs 2–4 mm long; panicles 15–30(–40) cm long, 2–8(–15) cm wide, usually partially enclosed
by the subtending sheaths; spikelets 1.5–2.3(–2.8) mm long; lemma ca. as long as or slightly
longer than the upper glume. Grasslands, disturbed sites, sandy soils; throughout TX except
Pineywoods; s Canada and throughout most of the U.S. May–Nov. The grains were consumed by
Native Americans (Mabberley 1987); they were apparently ground into a flour and then baked
(Yatskievych 1999).
Sporobolus indicus (L.) R. Br., (of India), SMUT GRASS. Perennial; culms 30–100(–120) cm tall;
panicles 10–30(–50) cm long; spikelets 1.4–2(–2.6) mm long; pericarp mucilaginous, the seed
often sticking instead of falling readily. Moist soils, often in disturbed areas; widespread in e 1/3
of TX, sparsely scattered further w; e U.S. from NY s to FL w to MO, OK, and TX, also CA, MI,
and OR. Mar–Dec. Native to Asia. The common name, SMUT GRASS, refers to the infection and
blackening of the inflorescences and upper leaves by a fungus (Bipolaris spp.) (Peterson et al.
2003). I