COMMON NAME
Japanese sedge
Asiatic sand sedge
FULL SCIENTIFIC NAME
Carex kobomugi Ohwi.
FAMILY NAME COMMON
Sedge family
FAMILY SCIENTIFIC NAME
Carex kobomugi
IMAGES
 Habit |
 Close-up of inflorescence |
 Incursion |
 Habitat/Incursion |
 Habitat/Incursion |
NOMENCLATURE/SYNONYMS
Synonyms: None
DESCRIPTION
Carex kobomugi is a perennial sedge that grows 10-30 cm (4 in.-1 ft.) in height. The plant is very stout and has an overall yellow-green color. The slightly arching leaves are very stiff and measure 3-6 mm (0.1-0.25 in.) in width. The margins of the leaves are rough to the touch, and the serration can be seen with the aid of a hand lens (10x). These leaves are often longer than the triangular stems. Carex kobomugi flowers in May to June. It is dioecious, therefore there are separate male and female plants. There are many flower spikes on this plant that appear as one large spike. The staminate (male) spikes are cylindrical in shape and measure 3-4 cm (1-1.5 in.) long and 1-2 cm (0.4-0.75 in.) wide. The pistilate (female) spikes are more ovoid in shape and measure 3-6 cm (1-2.25 in.) long and 2-4 cm (0.75-1.5 in.) wide. The perigynia are erect and dark brown in color, lance-ovate to elliptic in shape and measures 10-14 mm (0.4-0.5 in.) in length. The beak of the perigyna is smooth, bidentate and can measure nearly as long as the rest of the structure. The achene contained within the perigynium is trigonous in shape and measures 4-7 mm (0.15-0.25 in.) long. Page References Fernald 303, Gleason & Cronquist 709, Holmgren 661,Magee & Ahles 267. See reference section below for full citations.
SIMILAR SPECIES
Ammophila breviligulata Fern. (American beachgrass)
Panicum amarum Elliott (bitter panicum)
Ammophila breviligulata has dense inflorescences that measure 10-40 cm (4-15 in.) long and 1-2.5 cm (0.4-1 in.) wide, and its leaves are 2-ranked. Panicum amarum is glaucous and also has 2-ranked leaves.
REPRODUCTIVE/DISPERSAL MECHANISMS
Carex kobomugi has mechanically dispersed seeds. However, these seeds have a low germination rate, and seedlings are rarely seen. Usually this plant spreads locally by means of extensive rhizomes.
DISTRIBUTION
Carex kobomugi is native to coastal Japan, China and Korea. In the United States it has been reported down the east coast from Massachusetts to North Carolina, and also in Oregon. In New England this plant has been found in Massachusetts (historically) and Rhode Island.
HISTORY OF INTRODUCTION IN NEW ENGLAND
The first report of Carex kobomugiin the US was from Island Beach State Park, New Jersey in 1929. It was thought that perhaps it came ashore from shipwrecks that were carrying oriental porcelain, with this plant as a packing material. Soon after the plant was observed to be potentially good for the stabilization of dunes, and thus it was planted intentionally on the dunes in New Jersey and other beaches on the east coast. This plant likely made its way to New England through either intentional planting or the water dispersal of plant fragments or seeds.
HABITATS IN NEW ENGLAND
,Coastal Beach or DuneCarex kobomugi is found on the upper dunes of sandy beaches, and in sand pits near the coast.
THREATS
Carex kobomugi has the ability to form dense stands on coastal dunes. It has been found in densities of up to 200 plants per square meter. This density effectively excludes the native beach grass, Ammophila breviligulata. Carex kobomugi actually makes dunes more susceptible to being blown out, and the native plant diversity found with this sedge is less than with the native beach grass.
MANAGEMENT LINKS
Plant Conservation Alliance
Fact sheet including management information
DOCUMENTATION NEEDS
Documentation required: Specimen in fruit
Best time for documentation: Mid-summer
ADDITIONAL INFORMATION
Integrated Taxonomic Information System
Taxonomic information about the species
PLANTS Database
General information and map
Plant Conservation Alliance
Fact sheet
Virginia Native Plant Society
Fact sheet
Geological Society of America
Description of this plant in New Jersey