Northern Prairie Wildlife Research Center
SEDGE FAMILY (Cyperaceae)
IND. STATUS: OBL
FIELD CHARACTERISTICS: A perennial, clonal sedge with stems about 40-100 cm. tall and which usually exceed the leaves. Mature leaves are slender and green. Leaves and stems are extremely rough on the edges. Forms large tufts or hummocks to 30 cm. tall and as wide, although the authors have seen hummocks as tall as 75 cm. Flowering stems arise laterally. The lowest leaves are reduced to bladeless sheaths. Basal sheaths disintegrate into two rows of fibers on each side of a central fiber (pinnate, see Lake Sedge), and tend to be reddish-brown in color. The beakless perigynia are flat to flattened-convex, widest below the middle section of the body, and taper to the tip. Two stigmas are present. Nutlets are lens-shaped. Pincushion-like young shoots erupt in late summer, persist through the winter, and grow quickly in early spring into a tuft of bright blue-green leaves.
|Figure 21 - Perigynium and Scale|
One of the lake sedges (Carex aquatilis) is very similar to hummock sedge. C. aquatilis: lacks basal sheaths with two rows of fibers on each side of a central fiber; the flowering stems arise centrally; lowest leaves have blades; mature leaves tend to be blue-green; and stems do not form pincushion-like young shoots that persist through the winter.
ECOLOGICAL NOTES: Hummock sedge is the characteristic sedge of Minnesota and Wisconsin sedge meadows. It is also common in shrub-carrs and calcareous fens. The hummocks may persist for decades, even when pastured. Stands of hummock sedge provide excellent nesting habitat for rails and snipe. It is also called tussock sedge.
SOURCE: Gleason and Cronquist (1991); and Swink and Wilhelm (1994).