Palm Sedge (Muskingum sedge)
Carex muskingumensis Schwein.
Not in the Garden
Late spring flowering
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. Palm Sedge is a native perennial tufted sedge preferring a moist wetland/floodplain environment. The flowering stems (culms) are smooth, brown at the base and grow (usually) to 20 inches high, usually in a dense clump. Vegetative stems are most numerous. It is grown for the foliage.
Leaf Sheaths: Leaf sheaths are green in color, green veined to just short of the collar, U to V shaped. Ligules are about 2 mm long.
The leaf blades are 3 to 5 mm wide (to 0.2 inch) and up to 10 inches long, 'V' shaped, medium to light green in color turning yellow in the fall. There are 7 to 12 per fertile stem and more on vegetative stems. There are 3 columns of leaves on the stem, blades in each column lined up one above the other.
The inflorescence at the top of fertile stems is 5 - 9 cm long (up to 3-1.2 inches) and has 5 to 12 spikes, usually separated. Each spike is 12 to 28 mm in length, lanceloid in shape - that is widest below the middle, tapered base, an acute apex. The spikes are gynecandrous - that is, containing both staminate and pistillate florets. Styles have 2 stigmas. The perigynia are densely packed on the spike and appressed. (The bladder-like sacs that enclose the female flower and later the fruit are called perigynia, singular - perigynium). There are no bracts at the base of the spikes. The inflorescence is not too conspicuous as fertile stems are the minority, but are held high enough to top the leaves and are most noticeable as they turn brown to dark brown in the fall.
Each perigynium is pale brown, 5-7 veined on the back side and conspicuously 3-7 veined on the front, lanceolate in shape, flat surfaced with the body gradually tapering to a flat beak tip that is 3.1 to 4.5 mm from the achene. The body of the perigynium is 6-9 mm long and 2-2.5 mm wide, 0.3 mm thick with a flat thin wing 0.2-0.4 mm wide. The scales of the pistillate perigynia are about half the length of the perigynium and narrower with an acute tip, translucent or pale brown with a pale brown midstripe.
Seed: Mature fruit is a pale brown oblong achene, about 2 to 2.7 mm long by 0.8 to 0.9 mm wide. Florets are wind pollinated. Fruits may remain on the plant overwinter. Carex achenes usually require 60 days of cold stratification for germination - or sown outside in the Fall. Seeds are very light - about 40,000 to the ounce.
Habitat: Palm Sedge grows from a base of stout rhizomes, in wet mesic to wet conditions in bottomland forests and alluvial soils. Standing water is tolerated for short periods, such as bottomland flooding. Plants prefer sun but will do well in partial shade. In dense shade they will flop over. Soils should be kept moist.
Names: The genus name, Carex, is from the Latin, being the old name for Sedges. The species, muskingumensis, is named for the Muskingum River in Ohio, the original type local. The common name of Palm Sedge refers to the palm-like arrangement of the leaves. The author name for the plant classification - ‘Schwein’ refers to Lewis David de Schweinitz (1780-1834) German-American botanist and mycologist. Born in the United States and educated in Prussia. His primary work was in mycology. His classification for this species was published in 1824.
Comparisons: Palm Sedge is a member of the sedge Section Ovales, which is the largest section of Carex in North America, complex and difficult in identification, with fully mature perigynia considered best for identification.
There are few other sedges that will be confused with Palm Sedge if you consider the numerous and conspicuous vegetative stems and foliage, the spikes with tapered bases and acute tips, 12 to 28 mm long and the lanceolate perigynum body 6-9 mm long. Other species have spikes either shorter than 12 mm or longer but with rounded bases or apices or both.
Above: Palm Sedge plants are typically up to 20 inches high with many vegetative stems. 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 leaf sheath is V to U shaped with green veins approaching the collar section. 2nd photo - the back side of the sheath and the V shaped leaf.
Below: 1st photo - a developing inflorescence with 7 spikes, illustrating the shape. 2nd photo - drying mature perigynia with the achene inside.
Below: A vegetative stem showing the arrangement of leaf blades in 3 columns.
Palm Sedge is not present in the Wildflower Garden. The species is found only in the section of North America from the Mississippi Rive eastward into the Ohio valley - a total of 13 states plus Ontario where it was introduced. Within Minnesota it is rare, with known populations in only 8 counties, most concentrated on the southeastern side of the state, most along the river. It is currently listed on the DNR's "Rare Species" plant list. It is is one of over 150 sedges native to Minnesota.
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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.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"