Carex grisea (Wood Gray Sedge)

Plant Info
Also known as: Inflated Narrow-leaf Sedge, Ambiguous Sedge
Family:Cyperaceae (Sedge)
Life cycle:perennial
Habitat:part shade, shade; average to moist soil; deciduous woods, floodplain forest, forested stream and river banks, woodland ponds
Fruiting season:June - July
Plant height:6 to 36 inches
Wetland Indicator Status:GP: FACW MW: FAC NCNE: FAC
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Spikes: Flower shape: indistinct Cluster type: spike

[photo of spikes] Separate staminate (male) and pistillate (female) spikes, with a single staminate spike up to about ¾ inch long at the top of the stem. Below the staminate spike are 3 to 5 cylindric, all-pistillate spikes each up to 1 inch long, occasionally with a few staminate flowers at the tip (androgynous). Lateral spikes are usually widely separated, though the uppermost 1 or 2 pistillate spikes usually crowd the staminate spike. Lower pistillate spikes are longer stalked than upper spikes, the stalks smooth and mostly erect. Pistillate spikes each have a leaf-like bract at the base of the stalk that loosely sheaths the stem, the upper bracts usually greatly over-topping the terminal spike.

Leaves and stems: Leaf attachment: alternate Leaf attachment: basal Leaf type: simple

[photo of sheath and ligule] Leaves are basal and alternate, the widest 4 to 8.2 mm wide, erect to floppy, about as long as or shorter than the flowering stem. Stem leaf sheaths loosely wrap the stem and are papery, translucent whitish. The ligule (membrane where the leaf joins the sheath) is as long as or longer than wide. Leaves are hairless and smooth, M-shaped in cross-section when young.

[photo of basal sheaths] Bases are wrapped in a red-purple to brown sheath that is not fibrous. Stems are slender, 3-sided, hairless and smooth, erect to ascending, and may elongate up to 36 inches at maturity. Not all plants produce flowering stems. Plants typically form dense clumps.

Fruit: Fruit type: seed without plume

[close-up of maturing spike] 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 5 to 15 fruits, the perigynia ascending and loosely arranged on the stalk.

[photo of perigynia, scales and achene] Pistillate scales are egg-shaped, whitish to reddish-brown with a green midrib that usually extends to a rough-textured awn up to 5.3 mm long, the scale body about half as long as the perigynia, with the awn may be longer. Perigynia are green to yellowish-green, 4.2 to 6 mm long, 1.8 to 2.6 mm wide, hairless, shiny, slightly inflated, up to 64 impressed veins (10+ major veins with fainter veins between), elliptic, round in cross-section, tapering at the tip, the beak absent or minute, straight and toothless. Achenes are 2.6 to 3.7 mm long, weakly 3-sided in cross-section, widest above the middle, tapering to a stalk-like base and maturing to brown.


Carex grisea is a common sedge of floodplain forest and deciduous woods and reaches the northwestern edge of its range 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 grisea is in the Griseae section; some of its common traits are: clump forming or not, short to long rhizomatous, basal sheaths not fibrous, leaves M-shaped in cross-section when young, the leaf underside with 2 lateral veins more prominent than the midvein, widest leaves 6 mm or less, 3 to 6 spikes, terminal spike all staminate, lateral spikes mostly all pistillate, sometimes with a few staminate flowers at the tip (androgynous), lateral spikes subtended by a long-sheathing leaf-like bract, pistillate scales with a rough-textured awn, perigynia oval-elliptic and hairless with impressed veins (both fresh and dry), achenes 3-sided with 3 stigmas, usually growing in woodlands or open habitats.

Carex grisea is distinguished from other Carex species by the combination of: clump forming, usually densely so, all-staminate terminal spike, spike stalks smooth, lateral spikes usually all pistillate, usually fewer than 15 perigynia per spike, pistillate scales with a rough-textured awn, perigynia elliptic with up to 64 impressed veins, the minute or absent altogether.

Carex grisea most closely resembles Carex conoidea, which has rough-textured stalks on lateral spikes, typically more than 15 perigynia per spike, and is found in open prairies and meadows rather than wooded areas. Perigynia with minute beaks can resemble Carex oligocarpa, which is more strongly red-purple at the base, widest leaves are less than 4.5 mm, and the staminate spike may be well above the uppermost pistillate spike. Immature specimens may resemble a number of other woodland sedges, in particular Carex blanda, which has pistillate scales with awns only up to 1.5mm, perigynia with a short, bent beak and its raised (not impressed) veins are faint until dry.

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More photos

Photos courtesy Peter M. Dziuk taken in Fillmore County.


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