1. Phalaris arundinacea L. (reed canary grass)
a–c; Map 545
Plants perennial, with long, scaly rhizomes, forming large
clumps or colonies. Flowering stems 50–180 cm long. Leaf sheaths with the
ligule 3–7 mm long. Leaf blades 4–40 cm long, 7–15(–20) mm wide. Inflorescences
7–30 cm long, dense, but usually interrupted and noticeably branched panicles,
the branches strongly ascending. Glumes 3.5–6.5 mm long, glabrous or somewhat
roughened, the midnerve (keel) unwinged (rarely very slightly winged). Sterile
lemmas 1–2 mm long, linear, membranous or papery, not swollen or fleshy, hairy.
Fertile lemma 2.7–4.5 mm long, narrowly ovate, hairy, at least toward the tip.
Anthers 1.8–3.5 mm long. Fruits 1.5–2.0 mm long, elliptic‑obovate in
outline, brown. 2n=14, 27, 28, 29, 30, 31, 35, 42, 48. April–August.
Scattered to common nearly throughout Missouri, but still
apparently absent from portions of the Ozark Division (northern U.S. south to North Carolina, Oklahoma, and California; Canada, Alaska, Europe, Asia; introduced
sporadically in Mexico and in the Southern Hemisphere). Banks of streams,
margins of ponds and lakes, marshes, fens, and bottomland prairies; also
pastures, roadsides, railroads, and moist, disturbed areas.
This highly variable, circumpolar species sometimes is
planted for forage, hay, erosion control, or ornamental purposes, but
Steyermark (1963) noted that it can be weedy and difficult to eradicate once
established. He recorded it almost entirely from the Glaciated Plains Division
and stated that it was common only in the northwestern and north‑central
portions of the state. He suggested that a disjunct series of collections from Newton County made in 1954 might represent an introduction or escape from cultivation.
Since that time, the species has spread tremendously in Missouri and presumably
will eventually be found throughout the state. Populations south of the Missouri River are mostly found as large, dense stands along roadsides and the margins of
ponds and lakes.