Plants of the Eloise Butler Wildflower Garden

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. Pennsylvania Sedge is a cool season smaller dry-land sedge forming dense clumps. The flowering stems (culms) are triangular in cross-section, 5 to 18 inches high, green in color, usually smooth but the very upper portion may have some weak roughness. These rise singly from the rhizome and there are usually several alternate stem leaves. Bases are reddish.

The leaf blades are alternate along the stem and from the base, mid-green in color, smooth, grass-like, 0.5 to 3.6 mm wide. Base leaves are up 8 to 12 inches long, stem leaves shorter. The surfaces can be a little rough. The leaves arch over such that the leaf clump is rarely more than 8 inches high. In areas without severely cold winters some leaves will remain evergreen. New leaves are surrounded by many older dead leaves.

Leaf sheaths are light green, usually smooth with horizontal veining. The front area of the leaf sheath is V shaped.

The inflorescence consists of both pistillate (female) spikes and a staminate (male) spike above the pistillate ones. There can be 1 to 3 (4) pistillate, either separated or overlapping, and usually only one terminal staminate spike, usually on a short stalk above the pistillate. The inflorescence is subtended by a green bract that is shorter than the inflorescence itself in this species. The male spike is 8 to 24 mm long and 1.3 to 4 mm wide, brown with whitish stamens. The female spikes are much shorter, and have 4 to 13 perigynia. (The bladder-like sacs that enclose the female flower and later the fruit are called perigynia, singular - perigynium).

The perigynia are pale green when immature, ovate in shape, 2.2 to 3.4 mm long, 1.1 to 1.5 mm wide, vein-less, has very fine surface hair and taper to a straight beak of 0.5 to 0.9 mm in length. The scales on the pistillate perigynia are a dark reddish-brown with narrow white margins, ovate in shape, 2 to 4 mm long and 1.3 to 2.8 mm wide, or equaling the perigynium body, including beak, with the scale tips tapered to a point or more obtuse. Staminate scales are elliptic to ovate.

Seed: Female flowers have 3 slender white stigmas and when mature form a dark brown 3-sided achene. Florets are wind pollinated. Achenes need 60 days of cold stratification for germination.

Habitat: Pennsylvania Sedge is clump forming with cord-like reddish brown to dark brown horizontally spreading rhizomes. The stolons produced by the rhizomes spread and form plant colonies, which is this species primarily means of regeneration. It can re-seed but seedlings are considered rare and starting plants from seed is difficult. Unlike most sedges, Pennsylvania sedge prefers well drained upland sites with full to partial sun, particularly in the open forest understory and especially near oaks - hence one of the alternate common names - Common Oak Sedge. It has drought tolerance and tolerates shade. In dry shade conditions it will make a nice ground cover but not flower much. This is one of the first sedges to bloom, before Oaks leaf out. It is not eaten by White-tailed Deer, thus can make a low-maintenance ground cover. I does spread readily and is considered somewhat invasive if you do not have any control for it.

Names: The genus name, Carex, is from the Latin, being the old name for Sedges. The species, pensylvanica, refers to Pennsylvania, the original type location. 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: Pennsylvania Sedge is in the sedge section Acrocystis, characterized by plants with stoloniferous root systems, inflorescences in racemose form with staminate spikes above pistillate spikes, perigynia ascending with a base often spongy and usually beaked and with hair; perigynia scales 1 to 3 veined and rarely awned. Like most sedges, this one has several common names used by various sources. Pennsylvania Sedge is the accepted name used by USDA and USFS and by Minnesota authorities. The sedges in the Acrocystis Section similar to C. pensylvanica are C. lucorum and C. heliophila. The first is rare in Minnesota, the second not present. The main difference between C. pennsylvanica and C. lucorum is that in the latter, the beaks of the perigynia are longer, 0.9 to 1.6 mm, and the upper stems are strongly rough surfaces.