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Grasses and Sedges of the Eloise Butler Wildflower Garden

The oldest public wildflower garden in the United States

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Common Name
Upright Sedge (Tussock Sedge, Hummock Sedge)

 

Scientific Name
Carex stricta Lam.

 

Plant Family
Sedge (Cyperaceae)

Garden Location
Woodland - Marsh

 

Prime Season
May to June 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. Upright Sedge is a large perennial tufted sedge commonly forming tussocks (or hummocks) in wetlands and hence the alternate common names. The flowering stems (culms) grow 20 to 55 inches high, erect to arched, and are acutely angled with a rough surface on the angles.

The basal leaf sheaths are reddish-brown with reddish-brown spots on the front, do not have blades, are rough, and have a ladder-like vein structure known as ladder-fibrillose. Upper leaf sheaths have a V-shaped ligule that is longer than wide, tan to light yellow on the underside of the sheath and greenish on the upper side.

The upper leaf blades are only 4 to 6 mm wide and up to 2.5+ feet long, are green to bluish-green in color and also rough on the surface. The base of these leaves and the leafless sheaths below them, when they die down are what form the tussocks associated with the species.

The inflorescence consists of 3 to 6 spikes composed of 2 to 3 erect staminate (male) reddish-brown flower spikes with the terminal spike short stalked and the others without stalks; and just below them, 3 to 4 ascending pistillate (female) flower spikes. the lowest of which can be 1.6 to 10.8 cm long and 3 to 5 mm wide. These flowering stems arise laterally from the base of the plant, not from a stem. The bract that forms at the base of the inflorescence in most sedges is, in this species, shorter than or equal to the inflorescence itself and only 3 to 4.5 mm wide.

The perigynia (The bladder-like sacs that enclose the female flower and later the fruit are called perigynia, singular - perigynium) have a thickened acute beak (0.1 to 0.2 mm) , pale brown in color, sometimes with reddish-brown spots, ascending, ovoid but somewhat flattened, and can have 0 to 5 obscure veins on the face plus two marginal ribs. They very from 1.7 to 3.4 mm long and 0.8 to 1.8 mm wide. The scales of the female spikes are reddish-brown with usually white margins, shorter than the perigynia, with rounded to pointed tips and awn-less. The achenes are loosely enclosed.

Seed: There are two stigmas per flower. Mature fruit is a brown elliptic shaped achene with a beak at the tip.

 

Habitat: Upright Sedge grows from a short rhizome root system forming dense tussocks in marshes, bogs, wet swales and meadows. the species also has long rhizomes the branch and form offset plants. In warmer zones the plant remains evergreen whereas in more northern zones young leaf shoots resembling a pin cushion form in late summer, over-winter, and then grow in the spring. The species must have full sun, will tolerate partial sun, and is seriously degraded by the presence of invasive cattails and reed canary grass.

Names: The genus name, Carex, is from the Latin, being the old name for Sedges. The species, stricta, means 'erect' or 'rigid' referring to the upright flowering spikes. The name of the author for the plant classification, ‘Lam.’ refers to Jean-Baptiste Lamarck (1744-1829) French naturalist and biologist, an early proponent of evolution who among other things, published the 3 volume Flore Francaise. He is best known for his theory of the inheritance of acquired characteristics.

Comparisons: Upright Sedge is classified in the sedge section Phacocystis wherein the species have staminate spikes on the top of the stem and pistillate spikes below. Perigynia are erect to ascending with two prominent marginal veins and the pistillate scales usually are long-awned. Upright Sedge has variability in the amount of roughness on stems and leaves, color of the basal sheaths and length of the inflorescence bract. There are three other sedges in Minnesota that are similar in appearance: C. haydenii, (Hayden's Sedge) which is closest in size, form and inflorescence, does not have the ovoid flattened perigynia with short scales, but an inflated perigynia with longer scales and a rounded beak. Also the leaves and sheaths are not rough. C. aquatilis (Long-bracted Tussock Sedge) does not have the roughness on the basal leaf sheaths and the inflorescence bract is longer than the inflorescence; and C. emoryi (Emory's Sedge) has 3 to 5 distinct veins on the perigynia which is green, not pale brown and spotted, and the plant does not form tufts. Only C. haydenii forms tussocks but not on the scale of C. stricta. All three are found in Minnesota.

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

full plant drawing

Above: Upright sedge is a tall plant compared to other sedges. Leaf blades can be up to 2-1/2 feet long. Drawing from Prof. Dr. Otto Wilhelm Thomé Flora von Deutschland, Österreich und der Schweiz 1885, Gera, Germany, courtesy Kurt Stüber's Online Library

Below: The staminate (brown) spikes appear above the pistillate spikes.

inflorescence male flowers female flowers

Below: The perigynias formed on the pistillate spike. Sheath area of the blade, and the blade itself has 3 ridges forming a flattened V to M shape.

maturing florets ligule blade

Below: Two views of a staminate spike before flowering.

Staminate spike Staminate spike detail

Below: 1st photo - The reddish-brown basal sheaths with ladder-like veins. 2nd photo - the mature perigynia - photo ©Steve Hurst, USDA-NRCS Plants Database

basal sheaths perigynia

Notes:

Upright Sedge, also called Tussock Sedge or Hummock Sedge is one of over 150 sedges native to Minnesota. It is quite common with only 14 counties not reporting it. In North America it is found east of the Rocky Mountains with the exception of Oklahoma and Florida in the U.S. and Saskatchewan, Newfoundland and New Brunswick in Canada.

Eloise Butler first noted Upright Sedge growing in the Garden in 1916. 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.

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