5. Echinochloa walteri (Pursh) A. Heller
Map 658
Flowering stems 60–200 cm long, stout, erect or ascending
from often spreading bases. Leaf sheaths (at least the lowermost ones)
pubescent with pustular‑based hairs, rarely glabrous. Leaf blades 10–50
cm long, 8–30 mm wide, glabrous or roughened. Inflorescences 10–30 cm long, the
primary branches 1–6 cm long, ascending and relatively densely spaced, mostly
strongly overlapping along the main axis, all but the uppermost with several
short, secondary branches. Spikelets 3–5 mm long (excluding the awns), narrowly
ovate to oblong‑ovate in outline, mostly hidden by the mass of awns,
usually dark purple at maturity. Upper glume 2.8–4.8 mm long (excluding the
awn), ovate, tapered at the tip to an awn 2–12 mm long, usually roughened or
hairy, at least along the nerves, the hairs with or without pustular bases.
Sterile floret with the palea well developed and 2/3–3/4 as long as the lemma,
the lemma 2.8–5.0 mm long (excluding the awn), ovate, tapered at the tip to an
awn 10–60 mm long, usually roughened or hairy, at least along the nerves, the
hairs with or without pustular bases. Fertile floret with the lemma 3–5 mm
long, about 3 times as long as wide, narrowly elliptic, the tip relatively
firm, usually wrinkled but not withering at maturity, narrow and sharply
pointed, without a line of minute hairs at the base. Anthers 0.4–0.7 mm long. 2n=36.
September–October.
Uncommon, known thus far only from St. Charles County (eastern U.S. west to Minnesota and Texas, most commonly along the Atlantic and Gulf
Coastal Plains; Canada, Mexico, Central America, Caribbean Islands). Banks of rivers and sloughs.
Although Hitchcock and Chase (1951) included Missouri in the range of this species, it was not confirmed to occur in the state until
recently (Smith, 1996). This robust, beautiful species should be found
elsewhere in the state in the future, particularly along the Mississippi River
floodplain.