Sand Sedge
Carex muehlenbergii
Sedge family (Cyperaceae)

Description: This perennial sedge is 1-2' tall, consisting of a tuft of leaves and an unbranched culm that is erect, ascending, or leaning to one side. The culm is light green, 3-angled, and glabrous; it is slightly rough along the angles below the inflorescence. Several alternate leaves occur along the lower one-fourth of the culm; their blades are ascending to widely spreading and recurved. Leaf blades are up to 12" long and 2-4.5 mm. across; they are light green, glabrous, furrowed, and slightly rough along their margins. Individual leaf sheaths have one side that is translucent-membranous and 2 other sides that are light green and glabrous; they wrap around the culm tightly. Below the concave mouth of each sheath, its translucent-membranous side is somewhat stiff and thickened. Each culm terminates in an inflorescence that is -1" long and up to " across; it consists of 4-10 sessile spikelets that are overlapping to slightly separated. Some spikelets have a few staminate (male) florets and their scales at their apices, while the perigynia of pistillate (female) florets and their scales are located below. Other spikelets consist entirely of the perigynia of pistillate florets and their scales. Each spikelet has 6-16 ascending to widely spreading perigynia that are clustered together. The perigynia are 3.0-4.0 mm. in length, 2.0-3.0 mm. across, and plano-convex; they are ovate-orbicular in shape, tapering to a short beak with 2 minute teeth. For the typical variety of Sand Sedge, the perigynia have several longitudinal veins along their outer sides, while for var. enervis, the outer sides of the perigynia are veinless. The perigynia are glabrous and they vary in color from light green to yellowish brown. The pistillate scales are about the same length as the perigynia or a little shorter; they are ovate in shape, tapering to short awn-like tip. The pistillate scales have green central veins and membranous margins. Each female floret has a pair of yellowish brown to reddish brown stigmata. At the base of each inflorescence, there is a slender leafy bract up to " in length; one or two additional bracts of smaller size may occur within the inflorescence. The blooming period occurs from late spring to early summer, lasting about 1-2 weeks. The florets are cross-pollinated by the wind. Afterwards, the mature perigynia disarticulate from the spikelets and they are blown about by the wind. Individual achenes are about 2.0 mm. in length, ovoid-orbicular in shape, and somewhat flattened, tapering abruptly to a small point at their bottoms..  The root system is short-rhizomatous and fibrous.

Cultivation: The preference is full or partial sun, mesic to dry conditions, and sandy soil.

Range & Habitat: The native Sand Sedge is occasional throughout Illinois (see Distribution Map). Habitats include upland sand prairies, sand dunes, rocky upland woodlands, areas along railroads, and sandy fields. There is a preference for upland habitats with barren soil and reduced competition from other kinds of ground vegetation.

Faunal Associations: Various insects feed on sedges (Carex spp.) in upland areas. These species include such common aphids as Rhopalosiphum maidis (Corn Leaf Aphid), Schizaphis graminum (Spring Grain Aphid), and Sipha flava (Yellow Sugarcane Aphid). An introduced aphid, Iziphya flabella, has been found on Sand Sedge (Carex muehlenbergii) specifically in Mason County, Illinois. Many grasshoppers feed on the foliage of upland sedges and other plants. These species include Arphia pseudonietana (Red-Winged Grasshopper), Melanoplus angustipennis (Narrow-Winged Sand Grasshopper), Spharagemon collare (Mottled Sand Grasshopper), and Trachyrhachys kiowa (Kiowa Grasshopper). See the Grasshopper Table for a more complete list of these species. Some billbugs also feed on sedges and similar species; they include Sphenophorus callosus (Southern Corn Billbug), Sphenophorus costicollis (Sedge Billbug), and Sphenophorus costipennis. The larvae of billbugs usually burrow through the stalks of these plants. Among vertebrate animals, upland gamebirds and granivorous songbirds feed on the seeds of upland sedges. These species include the Greater Prairie Chicken, Ring-Necked Pheasant, Wild Turkey, Horned Lark, Snow Bunting, and others (see the Bird Table for more complete list of these species). A small mammal, the Prairie Vole, feeds on either the foliage or seeds.

Photographic Location:
A sand dune at the Oak Openings Nature Preserve in NW Ohio.

Comments: Sometimes the scientific name of this sedge is spelled Carex muhlenbergii. Other common names of this sedge are Muhlenberg's Sedge and Sand Bracted Sedge. The typical variety of Sand Sedge is more common in Illinois than var. enervis. Mohlenbrock (1999/2011) now classifies var. enervis as a distinct species, or Carex plana. In the past, Carex austrina (Southern Sedge) was regarded as a variety (var. austrina) of Sand Sedge, but it is currently classified as a distinct species. Considering the variations in taxonomy around this species, it is not surprising that this sedge can be difficult to distinguish from other similar sedges, such as Carex gravida (Heavy Sedge) or Carex mesochorea (Midland Sedge). However, it is more likely to be found in sandy habitats than these latter two species.