Wetland Plants and Plant Communities of Minnesota and Wisconsin

STERILE SEDGE

(Carex sterilis Willd.)

SEDGE FAMILY (Cyperaceae)

IND. STATUS: OBL

FIELD CHARACTERISTICS: A perennial herb with stems forming tufts 20-70 cm. high (Figure 31a). The many slender leaves (1-2 mm. wide) are 30 cm. or more long. The spikelets (Figure 31b) usually number four, and are stalkless. The perigynium (Figure 31c) is egg-shaped (up to 2 mm. wide) and often spreading or bent backward at maturity. The beaks of the perigynia are double-toothed and are dark brown at maturity. Nutlet is shown by Figure 31d. Half of the plants are sterile (staminate only), which gives this species its name.

Sterile sedge may be confused with interior sedge (Carex interior), which is similar but usually has only 3 spikelets per stem, and occurs in both bogs and calcareous inland fresh meadows, particularly those with fluctuating water levels.

ECOLOGICAL NOTES: Sterile sedge is a characteristic sedge of calcareous fens and other inland fresh meadows supported by stable, calcareous groundwater seepages. The authors have observed that, in Minnesota and Wisconsin, sterile sedge is an obligate calcareous fen species. Sterile sedge is listed as a threatened species by the State of Minnesota.

SOURCE: Fassett (1976); Gleason and Cronquist (1991); and Swink and Wilhelm (1994).

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