21. Carex eleocharis L.H. Bailey (needleleaf sedge)
Pl. 34 a–d; Map 134
Plants mostly monoecious, with slender,
light brown to brown rhizomes. Flowering stems 5–20 cm long, bluntly trigonous,
smooth. Leaf blades 3–15 cm long, 0.3–1.5 mm wide, thick, stiffly straight and
spreading to ascending or somewhat arching. Leaf sheaths thin at the tip. Heads
5–20 mm long, irregularly ovate to elliptic in outline, the 3–7 spikes 4–9 mm
long, 2–6 mm wide, with numerous conspicuous staminate flowers toward the tip
and 1–8 perigynia toward the base, the uppermost spikes sometimes entirely
staminate. Staminate scales 3.0–3.5 mm long. Perigynia 2.6–3.1 mm long,
including the 0.5–1.0 mm long beak, lacking nerves or with several nerves in
the basal half on one or both sides, straw-colored, turning dark brown to
nearly black at maturity. Fruits 1.6–1.8 mm long. May–June.
Introduced, known only from the city of St. Louis (western U.S. from Iowa west to Oregon and New Mexico; disjunct in northern Illinois and Michigan; Canada; introduced in central Illinois and Missouri). Adventive
along railroads.
The American C. eleocharis is often
combined taxonomically with the closely related Eurasian species, C.
stenophylla Wahlenb., which differs in having somewhat larger perigynia
with the ventral surface finely many-nerved.