Carex rosea (Rosy Sedge)

Plant Info
Also known as: Starry Sedge, Curly-style Star Sedge
Genus:Carex
Family:Cyperaceae (Sedge)
Life cycle:perennial
Origin:native
Habitat:part shade, shade, sun; dro to moist soil; deciduous woods, mixed forest, wooded ravines
Fruiting season:June - July
Plant height:8 to 36 inches
Wetland Indicator Status:GP: FACU MW: FACU NCNE: FACU
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Spikes: Flower shape: irregular Cluster type: spike

[photo of spike clusters] A cluster up to 2¾ inches long at the top of the stem, made up of 4 to 8 small spikes, those at the tip of the stem close to each other but not tightly crowded and the lower spikes all well separated from each other. All spikes are stalkless and have staminate (male) flowers at the tip and pistillate (female) flowers at the base (androgynous). At the base of each spike is a bristle-like bract, the lowest may be more leaf-like and may overtop 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 along the lower third of the stem, the largest up to 16 inches long and 1.8 to 3 mm wide, mostly shorter than the flowering stems, initially erect becoming arching. Stem leaf sheaths tightly wrap the stem and are translucent whitish, concave to straight across at the tip. The ligule (membrane where the leaf joins the sheath) is wider than long. Leaves are hairless, V-shaped in cross-section when young.

[photo of plant base] A few old, dead leaves are usually persistent to the next season. Bases are wrapped in a brown sheath that may become fibrous with age. Stems are erect to ascending to prostrate, slender, up to 2.2 mm diameter at the base, 3-sided, rough textured on the upper stem, elongating up to about 3 feet at maturity. Plants are densely clump-forming and not colony-forming. At maturity, the whole plant may flatten out in a radiating pattern.

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 each contain 1 to 14 fruits that are spreading to reflexed (downward pointing). The remains of the slender styles tend to persist in fruit, though readily detach from the achenes; the 2 stigmas are short and twisted or coiled 1 to 3 times.

[photo of maturing perigynia, scale and achene] Pistillate scales are egg-shaped to nearly round, translucent white with a green midrib, blunt to pointed at the tip, awnless, and are half to 2/3 as long as the perigynia. Perigynia are 2.6 to 4(4.2) mm long, 1.1 to 1.8 mm wide, green to yellowish brown at maturity, hairless, thickened and spongy at the base, flattened on the back side, veinless except for several lines along the spongy base on the back side (best seen at maturity), generally lance-shaped in outline, widest at or below the middle, rounded to straight across at the base and gradually tapering at the tip to a short beak that has minute teeth along the edges and 2 small teeth at the tip. Achenes are 1.6 to 2.2 mm long, 1.1 to 1.6 mm wide, flattened lens-shaped, broadest above or below the middle, and mature to brown.

Notes:

Carex rosea is a common sedge found in dry to mesic deciduous or mixed woods in the southern 2/3 of the state.

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 rosea is in the Phaestoglochin section; some of its common traits are: clump forming, basal sheaths usually fibrous, sheath fronts sometimes cross-wrinkled (rugose), leaves hairless and V-shaped in cross-section when young, 3 to 15 stalkless spikes (rarely the lower are branched), terminal spike with staminate flowers at the tip (androgynous), lateral spikes androgynous or all pistillate, perigynia ascending to spreading and flattened on the back side, rounded and spongy at the base, beaked, the beak usually toothed, flattened lens-shaped achenes.

Carex rosea is distinguished by the combination of: densely clump-forming, widest leaves 1.8 to 3 mm wide, up to 8 stalkless spikes with staminate flowers at the tip, spikes few-flowered and most widely separated, perigynia spreading to reflexed, 2.6 to 4+ mm long, spongy at the base, veinless except for lines on the spongy base, styles often persisting in fruit, the stigmas short and tightly coiled or twisted, and usually a woodland habitat.

Most similar is Carex radiata, which is overall less robust, has more numerous old persistent leaves, widest leaves are less than 2 mm wide, perigynia are slightly smaller (to 3.8 mm long), and the persistent stigmas are longer and more or less straight. When styles are missing check the leaf width and the presence of old, dead leaves for a determination. The arrangement of C. rosea perigynia is similar to some members of the Stellulatae section, which have staminate flowers at the base of a spike (gynecandrous) rather than the tip (androgynous).

Carex radiata and Carex rosea have a convoluted history. At one time we had C. rosea and C. convoluta, then C. rosea became C. radiata and C. convoluta became C. rosea (there should be a law against reusing names like that!). There is currently a mix-up of old Herbarium records for these two species and the distribution maps reflect that confusion. Someone will have to examine the old specimens and make new determinations before this is straightened out and the distribution within the state corrected.

Please visit our sponsors

  • Wild Ones Twin Cities Chapter

Where to buy native seed and plants ↓

Map of native plant purveyors in the upper midwest

  • Shooting Star Native Seeds - Native Prairie Grass and Wildflower Seeds
  • Morning Sky Greenery - Native Prairie Plants
  • Minnesota Native Landscapes - Your Ecological Problem Solvers
  • Natural Shore Technologies - Using science to improve land and water
  • Itasca Ladyslipper Farm - Native orchids, container grown

More photos

Photos by K. Chayka taken in Fillmore and Jackson counties. Photos by Peter M. Dziuk taken in Carver, Jackson and Wabasha counties.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Post a comment

Note: All comments are moderated before posting to keep the riff-raff out. An email address is required, but will not be posted—it will only be used for information exchange between the 2 of us (if needed) and will never be given to a 3rd party without your express permission.

For info on subjects other than plant identification (gardening, invasive species control, edible plants, etc.), please check the links and invasive species pages for additional resources.



(required)




Note: Comments or information about plants outside of Minnesota and neighboring states may not be posted because Id like to keep the focus of this web site centered on Minnesota. Thanks for your understanding.