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Georgian Court University
Carex macrocephala, the large headed sedge, grows on dunes in Russia, Japan and Western North America (Oregon to Alaska). However, until recently, the species had not been observed on the East Coast of North America. In the summer of 2005 my students and I discovered three stands of C. macrocephala in New Jersey. They are located at Sandy Hook, Seven Presidents Oceanfront Park and in Bay Head, NJ.
The stand at Seven Presidents is clearly visible from a number of well-used boardwalks but, because C. macrocephala is similar in appearance to Carex kobomugi, the former has probably been misidentified as C. kobomugi in the past. However, once the identification was correctly made, the differences were obvious. C. macrocephala in New Jersey has much more robust shoots than the closely related C. kobomugi , and grows in a much more sparse growth pattern (maximum of about 90 shoots / m2 versus over 500 shoots /m2). The leaves are longer, greener and the female seed heads are much larger, and feature seeds that are darker in color with sharp, bidentate beaks that easily embed in the skin if touched (see below).
Within their native ranges these two sedges are not known to co-occur. C. macrocephala tends to grow in the North Pacific (N. Japan, Russia, NW America), whereas C. kobomugi tends to grow in more southerly areas (Southern Japan, Korea, Taiwan). The presence of both species in close proximity to one another in New Jersey raises the possibility of the formation of a hybrid between these two closely related, wind pollinated species. This is of special concern because C. kobomugi is already creating serious ecological problems within New Jersey's dunes. Since hybrids are often more invasive than either parent species, the presence of a hybrid Carex in New Jersey could be catastrophic to the health of New Jersey's coastal dunes systems.
Learn to identify Carex macrocephala
Click here to read our initial proposal for our study of the related species C. kobomugi
Click here to see some pictures of us at work
Learn more about the Biology Department at Georgian Court University
Read more about what we've found out about Carex kobomugi (sister species of Carex macrocephala ) so far:
Author: Louise Wootton. Ph.D. Last updated Sept. 29, 2010