Carex torreyi (Torrey's Sedge)
|Also known as:|
|Habitat:||part shade, sun; moist to dry sandy or rocky soil; prairies, savannas, meadows, open woods, thickets, wooded bluffs|
|Fruiting season:||June - July|
|Plant height:||6 to 20 inches|
|Wetland Indicator Status:||GP: UPL MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Separate staminate (male) and pistillate (female) spikes, with a single staminate spike up to about 2/3 inch long at the top of the stem, rarely with a few pistillate flowers at the tip (gynecandrous). Just below the staminate spike are 2 to 4 (frequently 2) oval to cylindric, all-pistillate spikes each up to about ½ inch long, all near each other or sometimes the lowest more distant than the rest. Pistillate spikes are short-stalked to stalkless and erect to ascending; each has a leaf-like bract at the base of the stalk that is sheathless and may be longer than the associated spike but usually does not over-top the terminal spike.
Leaves and stems:
Leaves are basal and alternate, 1.5 to 3 mm wide, erect to ascending, much shorter than the flowering stem. Stem leaf sheaths are U to V-shaped at the tip and moderately to densely hairy. The ligule (membrane where the leaf joins the sheath) is longer than wide, an inverted V-shape, blunt to pointed at the tip. Leaves are hairy on both surfaces, V-shaped in cross-section when young.
Bases are wrapped in a reddish to brown sheath that may become fibrous with age. Stems are slender, 3-sided, smooth to sparsely hairy, mostly erect and may elongate up to 20 inches at maturity. Not all plants produce flowering stems. Plants form loose to dense clumps from short rhizomes.
Fruit develops in late spring through early summer, the pistillate spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Pistillate spikes have up to 30 fruits, the perigynia ascending to spreading, overlapping and crowded.
Pistillate scales are broadly egg-shaped to nearly round, reddish-brown to whitish with a green midrib that dries brown and usually abruptly tapers to a pointed tip; scales are much shorter than the perigynia. Perigynia are greenish-brown at maturity, 2.2 to 3.5 mm long, 1.5 to 2.2 mm wide, hairless, slightly inflated, distinctly 18 to 24-veined, round in cross-section, oval to somewhat urn-shaped in outline, abruptly tapered to a short, cylindric, toothless beak at the tip. Achenes are 2 to 2.5 mm long, weakly 3-sided to nearly round in cross-section, urn-shaped, widest above the middle, tapering at the base and maturing to brown.
Carex torreyi is an occasional sedge in Minnesota, found in dry to moist, often rocky soil in prairies, thinly wooded slopes, bluffs, and coulees (steep-walled valleys). Minnesota is on the southern edge of its range; it is currently listed as a Special Concern species in Wisconsin.
Carex is a large genus, with over 600 species in North America and 150+ in Minnesota alone. They are grouped into sections, the species in each group having common traits. Carex torreyi is in the Porocystis section; some of its common traits are: clump forming, short rhizomatous, basal sheaths reddish-brown and fibrous, leaves V-shaped in cross-section when young and usually hairy, widest leaves 8 mm or less, 2 to 6 spikes, bracts sheathless and thread-like or leaf-like, terminal spike all staminate or with pistillate flowers at the tip (gynecandrous), lateral spikes all pistillate or with a few staminate flowers at the base (androgynous), perigynia ascending to spreading and veined on one or both sides, perigynia usually beakless or with a toothless beak not more than .5mm long, achenes 3-sided with 3 stigmas.
Carex torreyi is distinguished from other Carex species by the combination of: clump forming, hairy sheaths and leaves, all-staminate terminal spike, 2 to 5 lateral all-pistillate spikes on erect stalks and mostly near the tip of the stem, hairless perigynia to 3.5mm long with 18 to 24 distinct veins and a short, cylindric, toothless beak. Carex torreyi most closely resembles the rare Carex pallescens, which has narrower perigynia that are weakly veined and have no beak, and is only found in the northeast counties where C. torreyi is rarely present.
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Photos by K. Chayka and Peter M. Dziuk taken in Wadena County.
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