Sedge family (Cyperaceae)
Description: This flatsedge is a summer annual about 2-6" tall. It sends up several culms from the base, otherwise it is unbranched. The culms are up to 4" long, light green, hairless, and usually 3-angled. There are 0-3 alternate leaves along each culm when the flowers bloom (older leaves become brown and withered). The leaf blades are up to 3½" long and 3 mm. across; they are light green, glabrous, linear, and shallowly furrowed along their central veins. Each culm terminates in 1-3 sessile (or nearly sessile) heads of spikelets; less often, heads of spikelets may be produced on short stalks (rays) up to ½" long. Each head consists of several ascending to spreading spikelets. Each spikelet is about ¼" (6 mm.) long and flattened, consisting of 6-10 flowers and their scales in two columnar ranks.
Each flower is enclosed in a single keeled scale; this scale is light green, hairless, and lanceolate, tapering into a strongly recurved and conspicuous tip. The flower is without petals and sepals, consisting of a single stamen and a tripartite deciduous style; the latter is barely exerted from the scale. At the base of the heads of spikelets, there are 2-3 leafy bracts that are up to 3½" long and 3 mm. across; these bracts are light green, glabrous, and linear like the leaves. The blooming period usually occurs from mid-summer to early fall. The flowers are cross-pollinated by the wind. As the achenes mature, the floral scales turn light brown; each flower produces a single achene. Mature achenes are about 1 mm. in length, oblanceoloid-oblongoid in shape, 3-angled, and brown. The root system consists of a shallow tuft of fibrous roots. This sedge often forms colonies in suitable habitats; it reproduces by reseeding itself.
Cultivation: The preference is full or partial sun and wet to moist conditions; this sedge grows in different kinds of soil, including those that are sandy, thin and rocky, or mucky. This flatsedge dislikes competition from taller plants. Because of its C4 metabolism, most growth and development occurs during the summer, rather than the spring.
Range & Habitat: The native Bearded Flatsedge occurs occasionally in central and NE Illinois, while in the southern and NW sections of the state it is less common (see Distribution Map). While this flatsedge is widely distributed, its populations tend to be scattered and local. Bearded Flatsedge also occurs in Eurasia and South America. Habitats include low-lying areas along rivers and ponds, prairie swales and sedge meadows, seeps, swampy woodlands, depressions in sandstone glades, crevices of sandstone cliffs, moist fields, and cracks along sidewalks and parking lots. This flatsedge typically occurs in wet areas with low vegetation, although it adapts as well to dry rocky areas (whether natural or artificial) where there are pockets of moisture. This flatsedge colonizes primarily disturbed areas where there is adequate light and sparse ground vegetation.
Faunal Associations: Flatsedges (Cyperus spp.) are host plants of various insects. The larvae of Diploschizia impigritella (Flatsedge Borer Moth) bore into the stems and leaf bases, while the larvae of Planetella caudata (Sedge Gall Midge) form cylindrical galls at the bases of these sedges. Various aphids suck plant juices, and a Blissid bug, Ischnodemus rufipes, feeds on the foliage. The seedheads and seeds of flatsedges are eaten to some extent by various birds, including the Green-winged Teal, Blue-winged Teal, Mallard, Northern Shoveler, Northern Pintail, Bobolink, Red-winged Blackbird, and Tree Sparrow (Martin et al., 1951/1961; Havera, 1999; Bellrose, 1942/1976). In addition to the seedheads, the Canada Goose also eats the foliage.
Photographic Location: This little flatsedge was growing abundantly in the cracks between a sidewalk and parking lot in Champaign, Illinois.
Comments: Bearded Flatsedge (Cyperus squarrosus) is easy to identify because its floral scales have strongly recurved tips. As a result, the spikelets have an odd saw-toothed appearance along their margins. The foliage and spikelets of young plants have a fresh spring-time appearance that is unusual for anything that grows during the middle of summer. Other flatsedges (Cyperus spp.) tend to be larger plants that produce their heads of spikelets on stalks and their floral scales lack strongly recurved tips. The floral scales of these other species are often some shade of yellow, red, or brownish purple during the blooming period. In contrast, the floral scales of Bearded Flatsedge are light green until after the blooming period is over, then they become light brown. Other scientific names that have been assigned to this species in the past include Cyperus aristatus and Cyperus inflexus.