13. Schoenoplectus torreyi (Olney) Palla (Torrey three-square, Torrey’s bulrush)

Pl. 81 h, i; Map 317

Scirpus torreyi Olney

Plants perennial with long-creeping rhizomes. Stems widely spaced on the rhizomes, 50–120 cm long, erect but usually relatively soft, strongly triangular in cross-section, the sides somewhat concave when fresh. Leaves 2–5 near the stem bases, all usually with well-developed leaf blades, these 3–70 cm long, the uppermost usually extending past the midpoint of the stem, V-shaped to flattened-triangular in cross-section. Leaf sheaths oblique at the tip with a V-shaped sinus on 1 side, usually split open with age. Inflorescences of 1–4 spikelets in a sessile, headlike cluster, the bracts 1–2, the main bract 4–15 cm long, the other if present much reduced (1–2 cm long) and stemlike. Spikelets 8–18 mm long, ovate to narrowly elliptic in outline, mostly pointed at the tip. Spikelet scales 4.0–6.5 mm long, ovate, tapered and not notched at the tip, with several additional veins parallel to and close to the midrib, tan to yellowish brown or brown, the green or straw-colored midrib usually tapered to a short awn. Perianth bristles 5–6, slightly shorter than to slightly longer than the fruits, relatively stout and straight or slightly arched around the fruit, retrorsely barbed. Stigmas 3. Fruits 3.0–4.5 mm long, obovate in outline, somewhat flattened, unequally triangular in cross-section, the surface smooth, yellow, turning greenish brown and eventually dark brown, somewhat shiny. 2n=42, 70. June–September.

Uncommon and possibly extirpated, known only from a single historical collection from Laclede County (northeastern U.S. and adjacent Canada south to Virginia, west to Nebraska). Emergent aquatics in relatively deep water of a sinkhole pond.