26. Panicum sphaerocarpon Elliott

Pl. 165 g–i; Map 687

Dichanthelium sphaerocarpon (Elliott) Gould

Plants perennial, with rhizomes absent, forming tufts. Flowering stems 10–60 cm long, erect or spreading, unbranched or the lower nodes becoming sparsely branched during the summer and autumn, the nodes glabrous or with short, appressed hairs, the internodes glabrous. Foliage in a dense rosette of shorter, slightly broader leaves at the base and longer, somewhat narrower leaves well distributed along the main stems, those of the later branches usually slightly shorter and narrower than those of the main stem leaves. Leaf sheaths glabrous on the surface, sometimes hairy along the margins near the base, occasionally with pale, glandular spots, the ligule absent or less commonly 0.3–0.8 mm long, a sparse line of hairs. Leaf blades of the main stems 3–20 cm long, 3–30 mm wide, mostly ascending, broadest near the base, rounded to heart‑shaped and sometimes somewhat clasping at the base, firm, hairy along the margins near the base, at least some of the hairs with pustular bases, glabrous on the surfaces, the main veins all similar or with the midvein slightly more prominent than the other veins, but not raised. Inflorescences 3–11 cm long, the earlier ones larger than the later ones, the branches loosely ascending to spreading, mostly rebranched 1 or more times, not spikelike or 1‑sided, the spikelets appearing mostly long‑stalked at the tips of the branches. Spikelets 1.3–1.9 mm long, broadly elliptic and nearly circular in outline. Lower glume 0.3–0.7 mm long, 1/4–1/3 as long as the spikelet, broadly ovate, rounded to very bluntly pointed at the tip, glabrous, nerveless or faintly 1–5‑nerved. Upper glume 1.2–1.8 mm long, broadly elliptic to nearly circular, rounded at the tip, 5–9‑nerved, finely hairy or less commonly glabrous. Lowermost floret sterile and with a reduced, inconspicuous palea, the lemma 1.2–1.8 mm long, broadly elliptic to nearly circular, rounded at the tip, 5–9‑nerved, finely hairy or less commonly glabrous. Fertile floret 1.4–1.7 mm long, broadly elliptic to nearly circular, rounded at the tip. Anthers 0.2–0.9 mm long. 2n=18. May–September (vernal), July–November (autumnal).

Scattered in the southern two‑thirds of the state (eastern U.S. west to Michigan, Kansas, and Texas; Mexico). Upland prairies, glades, ledges of bluffs, mesic to dry upland forests, bottomland forests, and banks of streams, usually on acidic substrates; also roadsides and open, disturbed areas.