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Sedges of Minnesota

The Eloise Butler Wildflower Garden is the oldest public wildflower garden in the United States

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Common Name
Fox Sedge (Brown Fox Sedge)

 

Scientific Name
Carex vulpinoidea Michx.

 

Plant Family
Sedge (Cyperaceae)

Garden Location
Not in the Garden

 

Prime Season
Late Spring to Early Summer flowering

 

Sedge Terms

 

Sedges differ from grasses by having a 3-angled stem and structurally different flowers where the female flowers are enclosed in a sac like structure called the perigynium, which is subtended by a single scale. Fox Sedge is a perennial clump-forming sedge, growing to 40+ inches high, but on stiff but thin (to 2.0 mm), unbranched stems (culms) without wings, with somewhat rough surfaces. Stems are usually brown at the base.

The leaf sheaths usually all have blades, the fronts rugose (cross-puckered), red-brown spotted or pale brown; with the apex convex to truncate, translucent to whitish. Ligules of leaf blades are rounded or with a slight notch, to 2 mm long with up to .2 mm free. Basal sheaths are fibrous.

The leaf blades are not more than 5 mm wide in this species and exceed the flowering stem in length, V to M shape when young, without hair, green in color.

The inflorescence is a terminal dense cylindric elongated cluster of spikes, 7 to 10 cm long and to 15 mm wide, with as many as 10 to 15 spikes, the lower spikes distinct from each other and the lowest having a small separation from the adjacent of up to 25 mm. The spikes are androgynous, that is with a staminate florets at the top and the pistillate florets below. The staminate are few in number. The perigynia are spreading to ascending when developed. (The bladder-like sacs that enclose the female flower and later the fruit are called perigynia, singular - perigynium). The bracts that form at the base of the lower spikes are thin and bristle-like, but visually apparent. These are usually without sheaths. The lower bract usually longer than the inflorescence.

Each perigynium is veinless on the front side, sometimes 3-veined on the back side. The body is green to pale brown. Perigynia are ovate to elliptic in shape, 2 - 3.2 x 1.3 - 1.8 mm, the base obtuse with some spongy tissue. The top tapers to a beak, 0.8 - 1.2 mm long, 1/3 to 1/2 as long as the body. The scales of the pistillate perigynia are smooth, pale brown with whitish edges and with an awn up to 3 mm long. There are two stigmas per pistillate floret.

Seed: Mature fruit is a reddish-brown ovate achene with a glossy surface, the style base deciduous. Each is about 1.2 - 1.4 mm long by 1 mm wide. Florets are wind pollinated. Seeds require 60 days of cold stratification for germination; they are so small and need light for germination that they must be surface sown.

 

Habitat: Brown Fox Sedge grows a long-rhizomatous root systems, forming clumps in wet to dry-mesic conditions but does best in moist open thickets, moist meadows, edges of riparian areas, wet woods and disturbed areas and most commonly in mesic to wet prairies. Plants prefer full sun but will grow in partial sun to shade if adequate moisture is provided.

Names: The genus name, Carex, is from the Latin, being the old name for Sedges. The species, vulpinoidea,' is from the Latin base word for fox and refers to the crowded spike clusters of the inflorescence resembling a fox tail. The author name for the plant classification - ‘Michx.’ refers to Andre Michaux (1746-1802), French botanist who made many exploring expeditions in the U.S. collecting and cataloging many species. His notes were later used by his son, Francois, who with Thomas Nuttall published the multi-volume North American Sylva.

The various common names using the words 'fox sedge', which have also been applied to several other species, refers to the resemblance of the inflorescence to a foxes tail.

Comparisons: Brown Fox Sedge is a member of the sedges in the Section Multiflorae, and has the distinguishing characteristics of V-shaped leaf blades when young, loosely clump-forming, sometimes with long rhizomatous roots, stem bases usually brown, paniculate type inflorescences with multiple condensed spikes - usually more than 15, spikes usually androgynous with lower spikes sometimes pistillate only, 2 stigmas per floret, pistillate scales yellow or brown, perigynia ascending to eventually spreading, spongy tissue at their base, achenes smaller than perigynia bodies.

The most similar sedges like this, found in Minnesota, are first, C. stipata, the Awl-fruit Sedge, where the sheath fronts are also rugose, the achenes are also ovate but the perigynia are veined on the front side and distended at the base and the stems have wings on the angles. Then there is C. alopecoidea, the Brown Head Foxtail Sedge where the sheath fronts are smooth, not rugose; the achenes are circular not ovate, and the perigynia are weakly veined on the back. C. conjuncta, Soft Fox Sedge is rarely found in the wild, however it has winged stems, a wider inflorescence, wider leaf blades, ovate perigynia with a beak half the body length and larger achenes with a persistent style base. Another similar sedge is C. crus-corvi, Raven's-foot Sedge, where the sheath fronts are smooth, the perigynia larger 6 to 8 mm - and they are prominently distended at the base. This sedge is also scarce - known only in Goodhue and Wabasha Counties.

The most closely related sedge, although fairly rare in Minnesota, is C.annectens, the Yellow-headed Fox Sedge. There, the flowering stem is much longer than the leaves, the perigynia are about the same size but are golden brown and conspicuously 3-veined on the back side and have short abrupt beaks. The species also prefers more dry soils.

See bottom of page for notes on the Garden's planting history, distribution in Minnesota and North America, lore and other references.

inflorescence drawing

Above: The inflorescence with its needle-like bracts. Drawing from Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York.

Below: 1st photo - The immature perigynia are green to pale brown, with a spongy base and tapering to a beak. 2nd photo - at maturity.

perigynia detail mature perigynia

Below: 1st photo - Inflorescence at maturity. 2nd photo - leaf blade with a definite keel. 3rd photo - the rugose front side of a sheath.

fall spike leaf blade leaf sheath

Below: The root system is rhizomatous, stems are brown at the base.

root basal sheath area

Notes:

Brown Fox Sedge is one of over 150 sedges native to Minnesota. It is one of the most wide-spread sedges in Minnesota with only a few counties not reporting it. In North America it is found in all the lower Canadian Provinces and all the lower 48 states of the U.S. except Utah.

In a reverse invasive situation, Brown Fox Sedge has taken hold in Europe to such an extent that papers have been published about it. See "On the spread of the North American Carex vulpinoidea Michx. in Europe and particularly in Austria" by B. Wallnofer, 2012, Annalen dis Naturhistorischen Museums in Wien.

References and site links

References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.

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