Carex hirtifolia (Hairy Wood Sedge)
|Also known as:||Pubescent Sedge, Hairy-leaved Sedge, Hairy Sedge|
|Habitat:||part shade, shade; average to dry, often disturbed soil; deciduous woods, thickets, wooded slopes, trail edges|
|Fruiting season:||June - July|
|Plant height:||10 to 24 inches|
|Wetland Indicator Status:||none|
|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 ¾ inch long at the tip of the stem. Below the staminate spike are 2 to 4 pistillate spikes, erect to ascending, and may be close together near the staminate spike, or more often the lowest spike is more widely separated from the one above it. Lower spikes are short-stalked, upper spikes are short-stalked to stalkless. At the base of a pistillate spike is a leaf-like bract that is longer than the spike but does not usually over-top the terminal spike.
Leaves and stems:
Leaves are basal and alternate, mostly near the base, 4 to 10 mm wide, up to 10 inches long, initially erect to ascending and becoming floppy. Stem leaf sheaths are U to V-shaped at the tip, translucent whitish, loosely or tightly surround the stem, and are covered in long, soft hairs. The ligule (membrane where the leaf joins the sheath) is longer than wide. Leaves are M-shaped in cross-section and variously covered in long, soft hairs, more densely so on the underside.
Bases are wrapped in a reddish brown to green sheath that is hairy and not fibrous. Stems are erect to arching, 3-sided, sparsely to densely covered in long, soft hairs but rough along the angles near the spikes. Stems can elongate up to 24 inches at maturity and are mostly longer than the leaves. Not all plants produce flowering stems. Plants form loose clumps and may create small colonies from short rhizomes.
Fruit develops in late spring to early summer, the pistillate spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Perigynia are mostly ascending and are not tightly crowded on the spike. Pistillate spikes each contain up to 25 fruits.
Pistillate scales are nearly round or widest above the middle, whitish and hairy along the tip edge, with a green midrib that often extends to an awn, scales on the lower part of the spike becoming about as long as the perigynia. Perigynia are 3.5 to 5 mm long, 1.5 to 1.8 mm wide, densely hairy, lack veins except for 2 prominent ribs, are 3-sided and somewhat spindle-shaped, the oval body abruptly narrowed to a stalk-like base (stipitate)wards the base and the tip, with a short straight beak that has 2 obscure teeth at the tip. Achenes are 2.5 to 2.8 mm long, 1.2 to 1.5 mm wide, 3-sided, widest near the middle, and mature to reddish brown.
Carex hirtifolia reaches the northwest edge of its range in Minnesota and is commonly found in upland woods in the southeast and central counties. It is tolerant of disturbance and can be seen along woodland trails and other shaded areas subject to disturbance.
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 hirtifolia is the lone member of the Hirtifoliae section (formerly Halleranae); some of its common traits are: loosely clump-forming and short-rhizomatous, stems hairy, basal sheaths reddish brown and not fibrous, leaves hairy and M-shaped in cross-section when young, terminal spike staminate, lateral spikes pistillate, pistillate spikes short-stalked to stalkless, pistillate scales on the lower part of a spike usually awned, perigynia hairy, perigynia veinless but for 2 ribs, achenes 3-sided in cross-section.
Carex hirtifolia is distinguished from all other MN sedges by the covering of long, soft hairs on leaves, stems and perigynia. While other sedges may have hairy leaves, stems or perigynia, this is the only species with all three hairy.
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Photos courtesy Peter M. Dziuk taken in Olmsted and Winona counties.
Have you seen this plant in Minnesota, or have any other comments about it?