307.
Carex
davisii
Schweinitz & Torrey, Ann. Lyceum Nat. Hist. New York. 1: 326. 1825.
Davis' sedge
Plants densely cespitose. Culms dark maroon at base; flowering stems 30—100 cm, as long as leaves at maturity or a little shorter, 1.5—3 mm thick, glabrous or pubescent on angles. Leaves: basal sheaths maroon, bladeless, sheaths pubescent or rarely glabrous; others grading from maroon to green on back, light brown-hyaline on front, red dotted and usually pubescent distally, prolonged at apex; blades flat, 3—8 mm wide, usually pubescent on abaxial surface at least near sheath, minutely scabrous on margins. Inflorescences: peduncles of proximal spikes slender, 10—25 mm, pubescent; peduncle of terminal spike 10—30 mm, pubescent; proximal bracts equaling or often exceeding inflorescences; sheaths 15—45 mm; blades 2—6 mm wide. Lateral spikes 2—4, 1 per node, well separated or distal 2 usually overlapping terminal spike, mostly erect when young but at least proximal spikes nodding at maturity, pistillate with 10—40 perigynia attached 1 mm apart distally and to 4 mm apart proximally, cylindric, 10—50 × 3.5—6 mm. Terminal spike gynecandrous, sessile or pedunculate, 15—35 × 2—6 mm. Pistillate scales pale hyaline with broad green midrib, elliptic or ovate-lanceolate, body shorter than mature perigynia but extending into pubescent green awn 2.5—3 mm, often short-ciliate near apex. Perigynia green to olive-green, often red dotted, 2-ribbed with 9—12 almost equally prominent, evenly spaced veins extending from base to apex, slightly inflated around achene, ellipsoid-ovoid, 4.5—6 × 2—2.5 mm, membranous, base rounded, apex narrowing abruptly to minute beak, glabrous; beak bidentate, less than 0.5 mm. Achenes distinctly stipitate, 2.2—2.7 × 1—1.2 mm, stipe 1 mm.
Fruiting late spring—mid summer. Floodplain forests; rich deciduous forests and forest margins, usually along streams or in ditches, wooded ravine slopes, meadows, fields and thickets; often associated with calcareous soils; Ont.; Ark., Conn., Del., Ill., Ind., Iowa, Kans., Ky., Md., Mass., Mich., Minn., Mo., Nebr., N.J., N.Y., Ohio, Okla., Pa., Tenn., Tex., Vt., W.Va., Wis.
Glabrous forms are sporadic in the western part of the range and were recognized as Carex davisii forma glabrescens by G. Kükenthal (1909) but do not warrant taxonomic recognition. A single collection of a putative sterile hybrid between C. davisii and C. hirsutella has been reported from Missouri (G. Yatskievych 1999+) but needs further study to confirm the parentage.
