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Wetland Plants and Plant Communities of Minnesota and Wisconsin

HARDSTEM BULRUSH

(Scirpus acutus Muhl.)


Hardstem Bulrush

SEDGE FAMILY (Cyperaceae)

IND. STATUS: 0BL

FIELD CHARACTERISTICS: A perennial herb from stout rhizomes. The stems are 1- 3(4.4) m. in height, cylindrical, and dark olive green, with a few sheathing vestigial leaves at the base. The stems may be 0.5-1 cm. thick and are small chambered so that they are stiff and not easily crushed between the thumb and index finger. There may be 1 spikelet or many, on stalks 7-20 mm. long. The spikelets are oval to cylindrical, exceeded by a specialized leaf that appears to be a continuation of the stem. Nutlets are 2.2-2.7 mm. long, totally covered by whitish-brown scales, and have 6 basal bristles. Scales have marginal hairs and red dots on the back. In flower from June to September.

ECOLOGICAL NOTES: Hardstem bulrush is a persistent emergent found in deep and shallow marshes, lakes, streams, and occasionally bog lakes; generally in water depths to 5 feet, but it has been found in much deeper depths. It prefers sandy to marly substrates with good water circulation in the root zone. It is also found in calcareous fens. Hardstem bulrush can form colonial stands or be intermixed with other emergents. It has a higher tolerance of mixosaline conditions than softstem bulrush (S. validus). Hybrids between hardstem and softstem bulrush (Scirpus acutus x validus) can occur.

Waterfowl and shorebirds eat the nutlets, which are an important and frequently used food. Muskrats and geese eat the rhizomes and stems. In general, bulrushes (Scirpus spp.) provide nesting habitat and cover for a wide variety of birds and furbearers, as well as spawning and nursery habitat for northern pike and other fish species.

SOURCE: Gleason and Cronquist (1991); and Voss (1972).


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