Sedges differ from grasses by having a 3-angled stem and structurally different flowers where the female flowers are enclosed in a sac like structure called the perigynium, which is subtended by a single scale. Stellate Sedge is a perennial tufted sedge usually found in forest edges and dry to moist woods. The flowering stems (culms) grow 8 to 35 inches high, erect to leaning in Mid-summer, unbranched with smooth surface except the upper areas may be rough to the touch. Stems are exceedingly narrow in width from 1.6 to 2.2 mm wide below to 0.5 to 0.9 mm wide near the top. Roots may put up multiple stems. Stem base have some brownish-purple coloration.
The basal leaf sheaths are tight and green with whitish-translucent fronts. Ligules are less than 2 mm long, wider than long with hyaline edges.
The widest leaf blades are only 1.8 to 2.6 mm wide, a rounded V shaped when young otherwise flat, smooth but the edges may be rough on some plants.
The inflorescence at the top of the stem has the spikes separated with the gap between the lower spikes at least 2x the length of the lower spikes. There are 4 to 8 spikes. The terminal spike is androgynous, that is, with both staminate and pistillate florets, the staminate at the tip, the pistillate below. The lateral spikes are usually all pistillate. Each spike can have 7 to 14 spreading perigynia - the spreading giving a rounded appearance to the spike - thus starry or stellate. (The bladder-like sacs that enclose the female flower and later the fruit are called perigynia, singular - perigynium). The bracts that form at the base of the spikes are thread-like, with the lower bracts up to 6 cm long, but less than 2x the length of the entire inflorescence. The lowest bract is either without a sheath or with one no more than 4 mm long.
Each perigynium is green in color, vein-less, the base of the body spongy and thickened, the spongy part not more than 20% of the perigynium length, the back side with longitudinal striations, the margins near the top finely serrate, ending with a beak 0.6 to 1.2 mm long with a pair of pointed teeth. The body of the perigynium is roughly 2.6 to 4 mm long and 1.1 to 1.8 mm wide. The scales of the pistillate perigynia have a translucent appearance with a green mid-vein; these are ovate to circular-ovate and mostly 1/2 the length of the perigynia and narrower with a pointed tip or short-awned. Scales turn to a light brown at maturity. There are two stigmas per pistillate floret which are tightly coiled (some say they look like Ram's horns) and rosy color when mature (thus - two of the alternate common names); and three stamens per staminate floret.
Seed: Mature fruit is a brown ovate to obovate shaped (basically 2-sided) achene, about 1.6 to 2.2 mm long x 1.1 to 1.6 mm wide. Florets are wind pollinated.
Habitat: Stellate Sedge grows from a short rootstock without conspicuous rhizomes, forming clumps in dry to wet-mesic deciduous forests, thickets, wood-edges where there is partial shade to full shade. Avoid full sun.
Names: The genus name, Carex, is from the Latin, being the old name for Sedges. The species, rosea, means 'rosy' or 'rose-like' and refers to the color of the stigmas. The author names for the plant classification are as follows: ‘Schkuhr’ refers to Christian Schkuhr (1741-1811) German artist and botanist who studied the flora of Wittenberg. One of his principal works was a monograph on sedges, with colored figures and containing a number of new species - title: Histoire des Carex ou laiches, contenant la description et les figures coloriées de toutes les espèces connues et d'un grand nombre d'espèces nouvelles of 1802. His work was recognized but amended by ‘Willd.’ which refers to Carl Ludwig Willdenow (1765-1812), German botanist, a founder of the study of the geographic distribution of plants. He was director and curator of the Botanic Garden of Berlin. The various common names come from the visual appearance of parts of the plant as covered above.
Comparisons: Stellate Sedge is a member of the short-headed bracted sedges in the Section Phaestoglochin, and has the distinguishing characteristics of clustered androgynous spikes containing ascending to spreading perigynia with scales no more that half the length of the perigynia body. The most similar sedge like this is C. appalachica, the Appalachian Sedge, the only real difference is the widest leaf blades are narrower, only 0.9 to 1.5 mm and the base of the stems is narrower - 0.7 to 1.4 mm wide. However, C. appalachica is not found in our area. The sedge in our area that is most confusing is C. radiata, the Eastern Star Sedge. There the only real noticeable difference without magnification is that the sigmas are either straight, twisted or only slightly coiled, and the spongy part of the perigynium is 20 to 30% of the perigynium length. There are very fine distinctions and confuse the experts unless you study a number of plants and plant parts over the growing season. Seeing the plants when the stigmas are fresh is the best distinction. Also C. radiata prefers a more moist environment.
Above: The inflorescence - the lower spikes are widely separated. Drawing from Britton, N.L., and A. Brown. 1913. An Illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York.
Below: Note the thread-like bract at the base of the inflorescence. 2nd photo - the stems may be multiple from the roots and the base have some brownish-purple coloring.
Below: 1st photo - The narrow leaf of this plant has a very fine rough edge. 2nd - Sheaths have green and white longitudinal lines on the outer side and - 3rd photo - on the inner side (front), ligules with hyaline edges the sheath shows a faint rugose pattern.
Below: 1st photo - A spike in flower. 2nd photo - fruiting spikes tend to lodge over against the thin leaves.
Below: Note the coiled reddish stigmas - an identifying characteristic. Photo of maturing perigynia.
Below: Semi-mature perigynia.
Stellate Sedge is one of over 150 sedges native to Minnesota. It is widespread in the state with a minority of counties, that are widely scattered, not reporting it. A cluster of those counties not reporting it are along the Dakota border. In North America it is found from the Great Plains eastward, including along the Gulf Coast, in the U.S. and in Ontario, Manitoba and Quebec in Canada.
Eloise Butler reported discovering C. rosea in the Garden on July 15, 1916. That was late in the season and due to the difficulty of identification once the stigma have dried, it is possible this discovery was C. radiata which she had identified earlier in the season on May 31. It has been noted in the Garden on both the 1986 and 2009 Garden Plant Census.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"