Sedge family (Cyperaceae)
Description: This perennial sedge is 1½–3' tall, often forming small loose tufts of fertile and sterile shoots (culms with alternate leaves). The culms are light green, 3-angled, and hairless or slightly hairy. The leaf blades are up to 12" long and 1/3" (8 mm. across); they are light to medium green and channeled along their midveins. The upper surface of each leaf blade is glabrous, while the lower surface is hairless to slightly hairy. The blades are ascending to widely spreading along each culm. The leaf sheaths are light to medium green and usually slightly hairy; the summit of the inner side of each sheath is concave or V-shaped. Plants with completely glabrous foliage occasionally occur, particularly in the western range of Davis' Sedge (Illinois & areas westward).
Each culm terminates in an inflorescence consisting of 2-5 spikelets and their leafy bracts. These spikelets are 1–1½" long and cylindrical in shape, consisting of 12-30 perigynia, florets, and their scales. Initially, the spikelets are erect and straight, but they often nod sideways at maturity on pedicels up to 1" long. The uppermost spikelet of each inflorescence is gynecandrous (pistillate florets above, staminate florets below), while the remaining spikelets are entirely pistillate. Shortly after shedding their pollen, the staminate florets wither away and their slender scales become light brown. The perigynia of the pistillate florets are 4.0–5.5 mm. long and 2.0 mm. across; they are ovoid-oblongoid in the shape with very short beaks. The outer surface of each perigynium is glabrous with 9-12 longitudinal veins that are evenly spaced. The perigynia are initially light green, but they become orange-brown at maturity. The pistillate scales are ovate with long awns; they are as long or longer than the perigynia. Immature pistillate scales have green midveins, otherwise they are membranous; at maturity, these scales become light brown and tend to spread outward from their perigynia. The blooming period occurs from late spring to early summer; the perigynia and their achenes disarticulate from the spikelets later during the summer. The achenes are 2.0–2.5 mm. long, ovoid in shape, and 3-angled; each achene is pointed at the bottom. The root system is fibrous and short-rhizomatous.
Cultivation: Davis' Sedge prefers partial sun or dappled sunlight, moist to mesic conditions, and loamy soil. The fertile culms have a tendency to lean sideways at maturity.
Range & Habitat: The native Davis' Sedge is common in most areas of Illinois (see Distribution Map), except in the SE section of the state, where it is less common or absent. Habitats include both upland and floodplain deciduous woodlands (usually where the tree canopy is somewhat open), wooded slopes along ravines and river valleys, woodland openings and alluvial meadows, powerline clearances in wooded areas, areas along woodland paths, and abandoned fields. This sedge can be found in either slightly degraded or higher quality habitats.
Faunal Associations: Various insects feed on Carex spp. (sedges). This includes Stethophyma spp. (Sedge Grasshoppers), Cosmotettix spp. (Leafhoppers), Plateumaris spp. (Leaf Beetles), and several butterflies, skippers, and moths (see Lepidoptera Table). Among vertebrate animals, many waterfowl, upland gamebirds, and granivorous songbirds feed on the seeds of sedges (see Bird Table); which birds are likely to use a particular sedge as a food source depends on its habitat. In general, sedges are eaten sparingly by mammalian herbivores.
Photographic Location: The upper photograph was taken at a powerline clearance in Busey Woods of Urbana, Illinois, while the lower photograph was taken along a path in a more shaded area of the same woodland.
Comments: Davis' Sedge is most noticeable when its spikelets become an attractive orange-brown during the summer, resembling the ripened grains of an agricultural crop. At maturity, this sedge is rather lanky and floppy. Davis' Sedge superficially resembles the common Carex grisea (Wood Gray Sedge), but it lacks the separate staminate spikelets of the latter species. The spikelets of Davis' Sedge are a little longer than those of Wood Gray Sedge, and it is more often found in sunnier habitats. The perigynia of both sedges are oblongoid-ovoid with beaks that are very short and straight. These perigynia are inflated, rather than flattened.