SafePlants

Cypress-knee Sedge (Carex decomposita)

Carex decomposita, commonly known as Cypress-knee Sedge, is a perennial sedge belonging to the Cyperaceae (Sedge) family.

Considerations for Pets

• The text mentions that Carex decomposita has a "short, stout, blackish rootstalk," but it does not indicate toxicity, which could present a chewing hazard for pets.

Taxonomy and Nomenclature

• Scientific Name: Carex decomposita Muhl.
• Common Name: Cypress-knee Sedge, Decomposite Sedge, Epiphytic Sedge
• Family: Cyperaceae (Sedge family)
• Synonyms: Flora of Virginia Name/Status: Carex decomposita Muhl.

Distribution and Habitat

• Carex decomposita is found throughout much of the eastern U.S., extending northwards.
• It is rare and local throughout its range, particularly in the north.
• It is only known from a few historical records in western New York and one from Oneida County.
• Favors inhospitably thick environments and alluvial land.
• Often found in association with cypress swamps and bottomland forests.

Morphological Characteristics

• It is a tufted perennial growing from a short, stout, blackish rootstalk.
• Fertile culms are 4-10 dm (40-100 cm) tall.
• Culms can range from 5-120 cm in height.
• Leaves have sheaths that are strongly dotted purplish red adaxially and concave at the mouth.
• Forms a dense tuft of foliage.
• Wider leaves compared to Bur-Reed Sedge.

Ecology

• Rare plant species found in Cypress Creek Swamp.

Associations

• Found in association with bald cypress trees (Taxodium distichum) and their cypress knees.

Further Information

• USDA-NRCS PLANTS Database
• Encyclopedia of Life
• Illinois Natural History Survey