7. Eragrostis frankii Steud. (sandbar love grass)

Pl. 147 c, d; Map 595

E. frankii var. brevipes Fassett

Plants annual, forming tufts. Flowering stems 8–30(–55) cm long, erect or ascending, sometimes from spreading bases, glabrous. Leaf sheaths usually with a tuft or line of hairs at the tip, otherwise glabrous, the ligule 0.2–0.8 mm long. Leaf blades 2–14 cm long, 1–4 mm wide, flat or with the margins inrolled, glabrous or roughened to hairy on the upper surface near the base. Inflorescences relatively open, broad panicles 4–12(–40) cm long, 1/3–1/2 the size of the entire plant, elliptic in outline, broadest near the middle, the branches loosely ascending to spreading, the axis and branches usually somewhat roughened. Spikelets 1.5–3.5(–5.5) mm long, 1.0–2.5 mm wide, mostly long‑stalked, mostly spreading from the branches, with 2–4(–9) perfect florets. Pattern of disarticulation beginning with the glumes, then the lemmas and fruits shed, leaving the persistent paleas and rachilla. Lower glume 0.7–1.5 mm long, 2/3 to about as long as the adjacent lemma, lanceolate, somewhat roughened along the midnerve. Upper glume 1.0–1.7 mm long, narrowly ovate, somewhat roughened along the midnerve. Lemmas 1.0–1.7 mm long, ovate, sharply pointed at the tip, keeled, the lateral nerves usually relatively conspicuous, roughened on the midnerve. Anthers 0.2–0.4 mm long. Fruits 0.4–0.8 mm long, broadly elliptic to nearly circular in outline, slightly flattened or with a very shallow, longitudinal groove, reddish brown. 2n=40, 80. August–October.

Scattered nearly throughout the state (eastern U.S. west to Minnesota and Oklahoma). Banks of streams and rivers, margins of lakes, ledges of bluffs, and less commonly moist depressions of glades, often in sandy soil; also fallow fields, roadsides, railroads, and open, disturbed areas.

Koch (1974) discussed the morphological differences between the more common tetraploid (2n=40) form of this species and the less common octoploid (2n=80) form, which he documented cytologically from a mixed population in Montgomery County. Tetraploid plants, which account for nearly all of the Missouri collections, are relatively small, finely tufted plants with spikelets less than 3.5 mm long and with mostly 2–4 florets. Octoploid plants are somewhat more robust, with larger, more diffusely branched inflorescences, longer spikelets with more florets, and slightly larger pollen. Sutherland (1986) noted that such plants are relatively common in eastern Kansas. Therefore, they should be found in adjacent portions of western Missouri in the future