by Ed Van Zandt   

A few years ago, May 12, 1998 to be exact, my wife Sheila and I were strolling the Hylebos boardwalk and stopped at the sinkhole location to admire the numerous flowering plants of the season.  While there, we noticed an interesting plant near the edge of the water pool. Upon taking a closer look we  were surprised to find a species of sedge - a species that we had never seen before at the Hylebos, or anywhere else for that matter. 

After taking some careful notes, the subsequent identification proved to be Carex obnupta with the usual common name of Tall marsh sedge.  Although this species is not threatened or endangered, it is not commonly observed and is widely considered a ‘species of concern.’  This basically means that the species is being monitored by government resource agencies and some preservation measures are in order.  Tall marsh sedge is usually found in shallow water or on very wet ground, especially along rivers or in coastal swamps.  The species ranges sporadically from the Cascade Mountains to the Pacific Coast and from southern British Columbia to northern California.

As sedges go, this species is quite attractive and is not difficult to notice.  The plant, which is a perennial, attains a height of about four feet tall with long bright green grass-like leaves, which are shorter than the plant height.  The flowers are arranged in drooping terminal spikes that are about two to three inches long, about a quarter of an inch thick and very dark brown in color.  The spikes also are covered with a large number of tan colored threads that support the florets.  The upper two or three floral spikes are composed of small female florets.  The lower four or five floral spikes are composed of male florets.  The Tall marsh sedge and a few additional sedge species can be found within the Hylebos preserve only because of the relatively undisturbed habitat.

Sedge species, along with several other closely associated plant groups, are part of the Cyperaceae which is commonly called the sedge family.  Some of the other plant groups in this large family, in addition to sedges, include spike rush, cotton grass, bulrush and beak-rush.  As a general rule, almost all of the species in these plant groups are found in moist meadows to open shallow-water habitats.  Sedges are quite a success story as there are about 4,000 species included in some 70 genera world-wide, and found on all of the continents, including Antarctica. The center of diversity for this family is tropical Asia and South America.  The majority of species that grow in the tropics are usually found at high elevations.  North America has about 530 species with the greatest development in the higher latitudes of both hemispheres.  The Pacific Northwest has a total of 133 native species. 

The main sedge plant stem is called the culm and is usually triangular in cross-section.  Less often the culm is terete (round) in cross-section. The leaves are usually three-ranked, which means they emerge at roughly the same height on the main stem. The male and female flowers are arranged in several ways depending on the individual species.  In some species, a portion of the floral spikes will be all male and a portion will be all female.  In the alternate situation, some species have floral spikes that contain both male and female flowers

Hopefully, the title question of this article has been answered and some appreciation has been acquired for one of the small treasures of the Hylebos.

Ed Van Zandt is a retired Weyerhaeuser forester. He teaches a class on the identification of native trees and shrubs at Highline Community College during Spring, Summer, and Fall quarters.