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Sedges of the Eloise Butler Wildflower Garden

The oldest public wildflower garden in the United States

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Common Name
Awl-fruit Sedge (Common Fox Sedge, Prickly Sedge, Owl-fruit Sedge)

 

Scientific Name
Carex stipata Muhl. ex Willd. var. stipata

 

Plant Family
Sedge (Cyperaceae)

Garden Location
Woodland

 

Prime Season
Mid-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. Awl-fruit Sedge is a perennial clump-forming sedge, growing to 48 inches high, but on thin (to 7 mm) unbranched stems (culms) with somewhat rough surfaces and usually a wing on the angles. Stems are spongy and can be easily compressed with the fingers.

The leaf sheaths usually all have blades, whitish to green, thin, and do not form an extension beyond the leaf base, strongly cross-wrinkled on the front (rugose) and are indistinctly veined and tear easily. Ligules of leaf blades are acute (pointed) 10 mm long with up to .8 mm free.

The leaf blades are not more than 10 mm wide in this variety and to 100 cm long, a V to M shape when young, coarse, without hair, green in color, sometimes. The longest blades will exceed one meter but are not longer than the stems.

The inflorescence is a dense cylindric elongated spike, up to 10 cm long with as many as 15+ branches, the lower spikes having a small separation from each other (up to 10 mm) and are distinguishable while the upper ones densely clustered, all giving a prickly appearance from the long beaks on the perigynia. (The bladder-like sacs that enclose the female flower and later the fruit are called perigynia, singular - perigynium). The spikes are androgynous, that is with a staminate florets at the top and the pistillate florets below. In this species there are only a few staminate florets. The perigynia are spreading to ascending. The bracts that form at the base of the lower spikes are thin to scale-like and insignificant. These are usually without sheaths.

Each perigynium is 15 veined on the front side, 7 veined on the back side. the body is pale green initially becoming pale brown at maturity with red-brown veins. The body is 4 to 5 mm long by up to 2 mm wide and tapers to a beak that is up to 2.5 mm long (less than half the body length) and has minute teeth. The overall shape is lanceoloid, slightly inflated (rounded) with a spongy base, smooth surfaced and with a distended base forming a short stalk (or stipe). The scales of the pistillate perigynia are smooth, membranous margins and a broad green central vein, lanceolate to ovate in shape, tapering to a narrow toothed tip. These are much shorter than the perigynia. There are two stigmas per pistillate floret.

Seed: Mature fruit is a brown flattened ovate achene with a smooth surface, with a persistent cylindric style base. Each is about 2.0 mm long by 1.5 mm wide. Florets are wind pollinated. Achenes need 60 days of cold stratification for germination.

 

Habitat: Awl-fruit Sedge grows a short rhizomatous root systems, forming clumps in wet to mesic conditions such as in marsh edges, wet and open thickets, wet meadows, edges of riparian areas and wet wood edges. Plants prefer full sun but will grow in partial sun to shade. C. stipata accepts slightly drier conditions than C. lacustris.

Names: The genus name, Carex, is from the Latin, being the old name for Sedges. The species, stipata, means 'crowded', referring to the crowded spikes on the inflorescence. The author names for the plant classification are as follows: First to publish was ‘Muhl’ which refers to Gotthilf Heinrich Ernst Muhlenberg (1753-1815) American Botanist who produced several catalogues of plants after retiring as a Lutheran pastor. His work was recognized but added to by ‘Willd.’ which refers to Carl Ludwig Willdenow (1765-1812), German botanist, a founder of the study of the geographic distribution of plants. He was director and curator of the Botanic Garden of Berlin. . The various common names come from the visual appearance of sharply pointed tips of the perigynia. The name 'foxsedge' is applied to several species and refers to the resemblance of the inflorescence to a foxes tail. The alternate name 'Owl-fruit' is probably a corruption of the common name for the main species, C. stipata, which is 'Awl-fruit' - 'awl' being a sharply pointed tool used in leather work and more accurately describes the pointed beaks of the perigynia.

Comparisons: Awl-fruit Sedge is a member of the sedges in the Section Vulpinae, and has the distinguishing characteristics of fairly wide V-shaped leaf blades, clump-forming short rhizomatous roots, stem bases usually black or brown, raceme type inflorescences with multiple condensed spikes, the spikes usually androgynous with lower spikes sometimes pistillate only, 2 stigmas per floret. There are two varieties of C. stipata: Var. stipata as denoted above and var. maxima, Stalkgrain Sedge where the leaves can be wider - 8 to 15 mm - the inflorescence longer - 10+ cm, and the perigynia larger - 5 to 6 mm. It is not found in Minnesota, but can be found south of Iowa and Wisconsin.

The most similar sedge like this, found in Minnesota, is C. alopecoidea, the Common Foxtail Sedge, where the sheath fronts are smooth, not rugose, the achenes are circular and the perigynia are obscurely 3 to 5 veined on the back side or vein-less. Two other close sedges in Minnesota are C. conjuncta, Soft Fox Sedge or Jointed Sedge, found only in Dodge and Rice counties, where the sheath fronts are rugose, achenes ovate, perigynia without a distended base and with 3 to 5 prominent veins on the back side. The other 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. Another closely-resembling species not in this sedge section, is C. vulpinoidea, Brown Fox Sedge. This has wide distribution in Minnesota. The stems are not as tall but stiff, the sheath fronts are rugose but spotted red-brown or pale brown, the leaves are narrow but longer than the flowering stem, the inflorescence has the lower spikes distinctly separated and subtended by needle-like long bracts. The perigynia, which are much smaller, take on a brown color as they are green to pale brown with pale brown scales and they have much shorter beaks.

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

plant Sheath spikes

Above:1st photo - tall erect culms with mature spikes. Photo ©Thomas S. Cochrane, University of Wisconsin. 2nd photo - detail of a rugose leaf sheath. 3rd photo - spike detail - both photos ©Linda Curtis, University of Wisconsin.

Below: Details of the perigynia and achenes, photo courtesy USDA-NRCS PLANTS Database / Hurd, E.G., N.L. Shaw, J. Mastrogiuseppe, L.C. Smithman, and S. Goodrich. 1998. Field guide to Intermountain Sedges. 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: Drawing of the leaf sheath (front view) and spike by Harry C. Creutzburg, ©Kenneth Kent Mackenzie (1940) North American Cariceae

sheath drawing spike drawing

Below: A comparison of the spikes, perigynium and achenes of some of the sedges from Sect. Vulpinae that are referenced in the "comparison notes" above. Drawing courtesy and ©Flora of North America

drawing of section Vulpinae

Notes:

Owlfruit Sedge is one of over 150 sedges native to Minnesota. It is widespread in the state with only 19 of the 87 counties not reporting it; most of those are in the drier SW and the farm counties of southern Minnesota where much wetland drainage has occurred. In North America it has broad distribution with all the lower Canadian Provinces reporting it and only Nevada, Texas, Louisiana, Arkansas, Mississippi and Florida in the U.S. not reporting it.

At Eloise Butler it has been noted in the Garden on both the 1986 and 2009 Garden Plant Census.

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.

©2015

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