Rosy sedge (Carex rosea) flowers and stems. Bottom right: part of a single fertile culm with two spikes; the lowest spike exhibits a very long basal bract. Top right: looking down parallel to the axis of a spike of rosy sedge. The single male floret is seen in (out-of-focus) cross section; the radiating female florets are seen in profile. Top right: a lateral view of a rosy sedge spike. Three of the female florets show brown remnants of the styles; two of the female florets still show styles with the three-loop twist (white arrows) characteristic of rosy sedge. Bottom left: a portion of a fertile culm; you can see the three-sided (triangular) shape. Near the bottom of the image is a single spike with a basal bract (labelled). The single male (♂) floret projects perpendicular to the plane of the radiating female (♀︎) florets.
Rosy sedge’s spikes are stalkless and occur in a cluster at the tip of the culm up to 2.75″ long. The cluster is composed of 4-8 small spikelets, crowded at the tip of the spike but well separated lower in the spike. Individual spikes consist of staminate (male) florets at the tip and pistillate (female) florets at the base, the individual florets radiating in all directions from the center of the spike. At the base of each spike is a bristle-like bract; the lowest bract in the cluster may be more leaf-like and may overtop the terminal spike. The staminate florets have anthers 0.8-1.3 mm long. The pistillate spikes produce fruit in late spring or early summer that consists of clusters of seeds (achenes) 1.6-2.2 mm long and 1.1-1.6 mm wide. The pistillate scales are 1.3-2.75 mm long. The perigynia are 2.6-4 mm long and 1.1-1.8 mm wide, green to yellowish brown at maturity, lance-shaped in outline and flattened on the back; they taper to a short beak with minute teeth along the edges and two larger teeth at the tip. The styles often persist in the fruit with the two twisted stigmas protruding. Each cluster of seeds is wrapped in a casing (perigynium) and subtended by an egg-shaped to nearly round pistillate scale, translucent white with a green midrib, blunt or pointed at the tip but lacking an awn.
Five fertile culms of rosy sedge (Carex rosea) in the middle of Wooded Island in early June. Note the widely spaced spikes and radiating florets within the spikes; one of the spikes has an exceptionally long basal bract. Two of the five bracts have buckled, always a risk with such a long, slender stem.
Rosy sedge (Carex rosea) is a native perennial sedge that typically grows 8-12″ tall but individual culms may get as long as three feet. Culms are three sided (“three square”), 1.6-2.2 mm wide basally, tapering to 0.5-0.9 mm distally; the upper parts of the culm are rough textured. Rosy sedge is clump-forming rather than colony-forming; at maturity the clump may flatten out in all directions. It prefers dry forests to mesic hardwood or mixed forests. The leaves may be either basal or occur alternately along the lower third of the culms. The leaves are up to 16″ long but only 1.8-3 mm wide, hairless, and V-shaped in cross section when young; they are mostly shorter than the culms and become arching as they mature. You’re unlikely to confuse rosy sedge with any of the other local sedges except the star sedge (Carex radiata) which also has culms that are triangular in section and, late in the development of the inflorescence, also has a “starburst” pattern of spikelets radiating in all directions. Star sedge has narrower (<2 mm) leaves than rosy sedge (3 mm) and star sedge has straight styles while rosy sedge has styles that curl through three turns; the styles in both species are red (assuming the styles are in their prime when you see them). Compare photos of the two species before deciding on an identification.


