Sedge family (Cyperaceae)
Description: This perennial sedge is about 1½–3' tall, consisting of a tuft of leaves and flowering culms. The erect to ascending culms are light green to green, 3-angled, glabrous, and rather spongy toward the base, becoming more slender at the apex where the inflorescence occurs. Alternate leaves are produced from both fertile and infertile shoots. The leaf blades are up to 2' long and ½" (12 mm.) across; they are light green to green, glabrous, and linear in shape. The leaf blades have a tendency to arch away from their culms; the larger blades are conspicuously furrowed along their central veins. The leaf sheaths are light green, longitudinally veined, and glabrous. The culm of a fertile shoot terminates in an inflorescence consisting of a terminal staminate spikelet (less often 2-3 staminate spikelets) and 2-7 pistillate spikelets. The narrow staminate spikelet is up to 4" long, light to dark brown (after releasing its pollen), and somewhat flattened; it can be nearly sessile, short-stalked, or long-stalked. The pistillate spikelets are up to 3½" long and 1¼" across; they are oblongoid-cylindrical in shape and densely crowded with the inflated perigynia of the pistillate florets. These perigynia are mostly ascending; the lower perigynia are more widely spreading. Initially, the pistillate spikelets are light green to yellowish green, but they become yellowish brown to brown with maturity. The pistillate spikelets usually occur in a loose cluster on short slender peduncles.
The perigynia are up to 15 mm. (2/3") long and 6 mm. (¼") across; they are lanceolate-ovoid in shape, tapering to long narrow beaks. There are several fine longitudinal veins along the outer surface of each perigynium. The pistillate scales are smaller in size than the perigynia; they are lanceolate, tapering gradually into awned tips. Immature pistillate scales have green central veins and translucent margins; they become more brown at maturity. The blooming period occurs from late spring to mid-summer (rarely later), lasting about 1-2 weeks. The florets are cross-pollinated by wind. At this time, each pistillate floret has 3 curly white stigmata that are exerted from the beak of its perigynium. About one month after the blooming period, the inflated perigynia disarticulate from the pistillate spikelets; they have the capacity to float on water, distributing the achenes to new areas (there is one achene per perigynium). The achenes are about 3 mm. long and 3 mm. across; they are hexaploid in shape and sharply angular (shaped like 6-sided diamond crystals); they are often slightly knobby where 3 edges meet at lateral corners, and their sides are often slightly concave. The achenes are glabrous and, depending on their maturity, light green to brown. At the apex of each achene, there is a persistent style that is coiled or curved near its base; this style is longer than the achene. The root system is fibrous and rhizomatous. Occasionally, clonal offsets are produced from the rhizomes.
Cultivation: The preference is light shade to full sun, wet to consistently moist conditions, and mucky to slightly sandy soil. Occasional flooding is tolerated, although not for long periods of time. The leaf blades become a lighter shade of green in bright sunlight.
Range & Habitat: The native Hop-like Sedge occurs in widely scattered locations throughout Illinois, where it is uncommon. Habitats include wet to moist areas of bottomland woodlands, swamps, soggy meadows, low areas along streams, marshes, and roadside ditches. This sedge usually occurs in wetlands with overhead canopy trees, although sometimes it can be found in open sunny wetlands. These habitats can be either sandy or non-sandy. Sometimes this sedge is used in wetland restorations.
Faunal Associations: Caterpillars of the butterfly Satyrodes eurydice (Eyed Brown), caterpillars of various skippers (Euphyes spp., Poanes spp.), and larvae of various moths feed on wetland sedges (Carex spp.); see the Lepidoptera Table for a listing of these species. Other insects feeding on these sedges include sedge grasshoppers (Stethophyma spp.), semi-aquatic leaf beetles (especially Plateumaris spp.), Sphenophorus costicollis (Sedge Billbug) and other billbugs (Sphenophors spp.), leaf-mining larvae of the fly Hydrellia griseola (Lesser Rice Leafminer), stem-boring larvae of the flies Cordilura varipes and Loxocera cylindrica, the seed bugs Cymus angustatus and Oedancala dorsalis, the stink bug Eurygaster alternata, various aphids, and leafhoppers (especially Cosmotettix spp.). Among vertebrate animals, the seeds of wetland sedges are eaten by waterfowl, rails, and some songbirds (see the Bird Table for a listing of these species). The muskrat occasionally feeds on the rhizomes, culms, and young shoots.
Photographic Location: A restored marsh at the Prairie Ridge State Natural Area in Jasper County, Illinois.
Comments: This is one of the larger and more attractive sedges (Carex spp.) in Illinois – the large pistillate spikelets have a striking appearance, resembling a spiked-club or similar weapon of medieval warfare. Hop-like Sedge closely resembles Carex lupulina (Hop Sedge), and distinguishing between these two species can be rather difficult. The most reliable method of identification involves an examination of their achenes: Hop-like Sedge has non-flattened hexaploid achenes, while the hexaploid achenes of Hop Sedge are somewhat flattened. In the field, specimens with intermediate characteristics (e.g., with slightly flattened achenes) may be hybrids of the preceding two species. The common names of these sedges refer to the superficial resemblance of their pistillate spikelets to the fruits of Humulus lupulus (Hop Vine). Another common name of Carex lupuliformis is False Hop Sedge.