79. Carex tetanica Schkuhr
Pl. 51 j–m; Map 195
Flowering stems 20–60 cm long, relatively
slender. Leaves green to dark green, not glaucous. Leaf blades 3–20 cm long, 2.0–4.5
mm wide, relatively thin, minutely roughened or toothed along the margins, not
inrolled toward the base. Leaf sheaths with the ventral side papery and pale
green to light yellow, truncate to shallowly concave at the tip, the ligule
mostly longer than wide and V-shaped. Staminate spike 15–40 mm long, 2–4 mm
wide, the scales 3–4 mm long. Pistillate spikes 10–40 mm long, 3.5–5.0 mm wide,
with 6–20 perigynia in 2–4 irregular, vertical rows around the axis, the scales
1.8–3.0 mm long. Perigynia 2.5–3.5 mm long, 1.3–2.0 mm wide, the tip beakless
or less commonly with a minute, more or less bent beak. Fruits 2.0–2.5 mm long.
2n=56. May–June.
Presently known only from two sites in St. Francois County (northeastern U.S. west to Minnesota and Nebraska; Canada). Fens.
Steyermark (1963) thought this species to
be found only in loess hill prairies of northwesternmost Missouri. Specimens
from this region were subsequently redetermined as immature or slightly
aberrant material of C. meadii by Dr. A. A. Reznicek of the University
of Michigan, and the species was considered to be absent from Missouri until
the discovery of specimens from fens in St. Francois County by Dr. David
Castaner of Central Missouri State University. Carex tetanica eventually
should be found in other fens in the eastern Ozarks.
The distinctions between C. tetanica
and the closely related C. meadii are based mostly upon quantitative
characters of mature spikes and perigynia. Some specimens of C. meadii
from relatively moist habitats lack the characteristic grayish green coloration
and are less stiffly erect, with spikes and perigynia at the lower end of
variation for that species. These can be difficult to distinguish from C.
tetanica. However, the combination of fertile and vegetative characters in
the key above allow correct determination of virtually all specimens of these
species.