Cyperaceae: Carex praegracilis
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Family Name
Cyperaceae
Common Name
Clustered field sedge, expressway sedge
Native American Name
Lakota: pȟeží psuŋpsúŋla
Description
Carex praegracilis is a perennial sedge in the Cyperaceae family. It grows from a dense, fibrous root system with long, creeping rhizomes, forming loose to dense sods and spreading readily by vegetative means. Stems (culms) are upright, slender, sharply three-angled, usually 20–70 cm tall, and smooth or slightly rough near the inflorescence. Leaves arise mostly from the base, with sheathing leaf bases that are smooth and light brown to tan and may be tinged reddish-brown. Leaf blades are narrow and flat, typically 2 to 4 mm wide often shorter than the culms, with rough margins. The ligule is a short, membranous, translucent structure about 1 to 2 millimeters long, often acute or truncate with smooth or slightly jagged edges, located at the junction of leaf blade and sheath. Flowering occurs from late spring to early summer (May–July). Inflorescences are terminal, composed of 2–5 short, cylindrical spikes, slender, erect, bearing numerous small spikelets clustered at the top of the stems. The species is usually monoecious, with staminate (male) flowers in terminal spikelets and pistillate (female) flowers in lateral or lower spikes, though some may be androgynous. Floral scales subtend florets with three stamens in male flowers and a single ovary with one style (dividing into two stigmas) in female flowers. Pistillate flowers are enclosed in a sac-like perigynium, which is green to brown, 2.5–4 mm long, and about 1 mm wide, with a short, straight beak. The achene (seed) is lenticular, brown, and about 1–1.5 mm long, maturing from early to midsummer. Clustered field sedge is native to South Dakota, commonly found in moist to wet meadows, prairies, roadside ditches, alkaline flats, and disturbed soils. It is distributed statewide but is especially abundant in low, moist sites and along roadsides.
Horticulture Notes
Seed Collection: Seeds are mature when perigynia turn brown and dry and detach easily, typically in early to midsummer.
Germination: Seeds require 60–90 days of cold stratification and exposure to light for best results; sow in fall or after stratification in spring.
Vegetative Propagation: Readily propagated by division of rhizomes or clumps in early spring or fall.
Soils: Tolerates a wide range of soils, from clay to sand, including alkaline and saline soils.
Light: Grows in full sun to light shade.
Water: Adapted to moist to moderately dry conditions; tolerates seasonal flooding and some drought once established.
Additional Notes
Clustered field sedge is native and widely used in restoration, landscaping, and erosion control, particularly in bioswales, rain gardens, and turf alternatives due to its tolerance of mowing and foot traffic. It provides cover and food for native insects, small mammals, and birds.