Carex deflexa (Northern Sedge)
|Also known as:
|part shade, shade, sun; moist to dry; swamp and bog edges, mixed and conifer forests, rocky woods, cliffs, rock outcrops
|May - June
|2 to 12 inches
|Wetland Indicator Status:
|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 5.7 mm (¼ inch) long at the tip of the stem. Just below the staminate spike are 2 or 3 pistillate spikes, each up to 6 mm long, stalkless or nearly so, all usually crowding the staminate spike. There is often also a short-stalked all-pistillate spike near the base of the stem.
Leaves and stems:
Leaves are basal and alternate, mostly near the base, 1 to 2.6 mm wide, erect to spreading, often longer than the flowering stem, with old leaves persisting to the next season. The ligule (membrane where the leaf joins the sheath) is as long as wide. Bases are wrapped in a reddish brown to purple sheath that may become somewhat fibrous. Stems are erect to ascending, slender, weakly 3-sided, and mostly smooth except on the upper stem. Stems may elongate up to 9 inches at maturity and usually remain shorter than the leaves. Plants form loose clumps from short, slender rhizomes.
Fruit develops in late spring, the pistillate spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Each pistillate spike contains 2 to 15 fruits, the perigynia erect to ascending, overlapping and crowded on the spike.
Pistillate scales are 2 to 2.8 mm long, egg-shaped to nearly triangular, pale to dark reddish-brown with whitish edging, tapering to a pointed tip, lacking awns, and are as wide as but shorter than the perigynia. Perigynia are 2.3 to 3.1 mm long, 1 to 1.4 mm wide, moderately hairy, 2-ribbed, olive green to brown at maturity, the body spherical and round in cross-section, the base initially spongy but shriveling to a stalk-like structure (stipe), and abruptly tapering to a straight or slightly bent green beak .4 to .8 mm long that has 2 minute teeth at the tip. Achenes are 1.3 to 1.6 mm long, 1 to 1.4 mm wide, generally oval in outline, round to weakly 3-sided in cross-section, and mature to brown.
Carex deflexa is an occasional sedge primarily found in rocky forests, shaded cliffs, outcrops and wetland edges, and reaches the southwestern edge of its range in Minnesota. There are 2 recognized varieties: var. boottii (sometimes included in C. rossii instead) is a more stout western species with staminate spikes to 11 mm long; var. deflexa is as described above and is found in Minnesota.
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 deflexa is in the Acrocystis section (formerly Montanae); some of its common traits are: mostly dry habitat, hairless leaves, basal sheaths typically fibrous, small spikes often tightly clustered, terminal spike staminate, perigynia typically hairy, perigynia with 2 small teeth at the tip of the beak, achenes 3-sided to round in cross-section.
Carex deflexa is distinguished by the combination of: clump-forming, red basal sheaths that are not much fibrous, widest leaves less than 3 mm wide, single terminal staminate spike, usually a pistillate spike near the plant base, the lowest non-basal spike with a leaf-like bract that usually overtops the terminal spike, pistillate scales shorter than the perigynia, hairy perigynia not more than about 3 mm long with a round body and short bent beak.
Carex deflexa is one of a group of 4 members of Acrocystis that have pistillate spikes at the base, the others are Carex rossii, Carex tonsa, and Carex umbellata. Of these 4, C. deflexa and C. rossii both have leaf-like bracts at the base of the lowest non-basal spike and pistillate scales shorter than the perigynia, where the other two have bristle-like bracts and scales about as long as the perigynia. C. rossii perigynia are larger, 3 to 4.5 mm long, the body more elliptic and with a longer beak. Also similar is Carex peckii, which lacks basal spikes, its fruiting stems are usually longer than the leaves, the lowest bract does not overtop the terminal spike, perigynia are 3.2 to 4.2 mm long with a shorter but toothier beak, and the perigynia body and achenes are more elliptic.
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Photos by K. Chayka and Peter M. Dziuk taken in Cook County and the garden.
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