Prairie:
Grasses, Rushes & Sedges

Grasses are usually the most abundant plants in coastal prairies and grasslands. Rushes and sedges are grass-like plants that often grow in or adjacent to the seasonally wetter areas in coastal grasslands. Most often they are perennials.

The scientific names for the species are taken from the Jepson Manual of Vascular Plants of California, Second Edition (Baldwin et al. 2012).

Brownhead rush inflorescence. Photo by D. Immel-Jeffery 2011.
California brome inflorescence

A comparison of grasses, sedges, and rushes

Grass Family (Poaceae)

Grasses have round stems and flat leaf blades. The stems, called culms, are usually hollow and jointed with solid nodes. The most conspicuous grasses are perennial bunch grasses. Bunch grasses form tufts, clumps, or tussocks by sending up new shoots called tillers. The tillers remain attached to the base of the grass and the plant gradually thickens. Because bunch grasses do not spread out like rhizomatous grasses, they provide an open structure to coastal prairie that enhances biodiversity: the spaces between bunches allow room for a diverse selection of forbs, mosses and other grasses to grow and provide habitat for feeding, nesting, and hiding birds and animals (Darris and Gonzalves 2008).

Sedge Family (Cyperaceae)

Sedges often have triangular stems. The female flowers of sedges are enclosed in a single sheath-like scale called a perigynia. Many sedge species spread through long rhizomes making them useful in erosion control of moister soils. The Sedge Family groups several related genera including Scirpus, Rhynchospora, Eleocharis, Cladium, Schoenoplectus & others, but the largest genus is the Carex with over 130 species growing in California, most of them native.

Rush Family (Juncaceae)

Most rushes have round stems and leaf blades. One exception discussed here is Juncus phaeocephalis, which has flat leaves and stems with overlapping bases much like an iris. However, both flat and round leaves usually have septa, characteristic partitions inside the leaves of most Juncus species, which can be seen when held up to the light or felt by sliding your fingers down the leaf.

The following table provides a comparison of general characteristics of grasses, sedges and rushes. Exceptions are listed under species discussed below.

Types of Geophytes
Group
(Genera)
Stem
(culm)
Leaf Blade Leaf Sheath Fruit
Grasses round, (usually) hollow; jointed flat open caryopsis (grain)
Sedges triangular, solid flat closed nutlet or achene enclosed in perigynium
Rushes round, solid (pithy) round (usually), with septa (partitions) either seeds enclosed in capsule

grasses

California oatgrass
(Danthonia californica)
Native

California oatgrass (Danthonia californica) plant with roots at the Oakland Museum. Photo courtesy of Mark Stromberg.
California oatgrass panicle and flower (enlarged). 1950, Manual of the grasses of the United States. USDA Miscellaneous Publication No. 200. Drawing courtesy Wikimedia Commons.
Nematode leaf galls (Cynipanguina danthoniaea ) on California oatgrass (Danthonia californica) near Fort Ross , Sonoma County California. 1 July 2010. Photo by D. Immel-Jeffery.

Tufted hairgrass
(Deschampsia cespitosa)
Native

Tufted hairgrass (Deschampsia cespitosa) growing with Douglas' Iris at Sonoma Coast State Beach. 2010 May 10. Photo by D. Immel-Jeffery.

Pacific reedgrass
(Calamagrostis nutkaensis)
Native

Pacific reed grass (Calamagrostis nutkaensis) along Kortum Trail, California State Parks, Russian River District. Photo by D. Immel-Jeffery 2010.

Purple needlegrass
(Stipa pulchra, formerly Nassella pulchra)
Native

Purple needlgrass inflorescence. Photo courtesy of the Santa Monica Mountains National Recreation Area, National Park Service

Red fescue
(Festuca rubra)
Native

Red fescue at Mount Burdell Open Space Preserve in Marin County. Photo by D. Immel-Jeffery 2010.

Blue wild rye
(Elymus glaucus)
Native

Blue wild rye flower spike. Photo Copyright © 2006 Laura Ann Eliassen.

California brome
(Bromus carinatus var carinatus)
Native

California Brome along Ridgecrest Trail, California State Parks, Marin. Photo by D. Immel-Jeffery 2010.

Meadow barley, California barley
(Hordeum brachyantherum)
Native

Meadow barely forms slender bunches often in dense stands such that the bunched habit is not readily evident. Moist understory, meadow, and riparian settings are likely habitats for this species. The inflorescence is held erect, in contrast to Hordeum jubatum, a morphologically similar species. Matt Lavin, Wikimedia Commons.

Sedges

Dense sedge
(Carex densa)
Native
Inflorescence and cross-wrinkled leaf sheath of dense sedge (Carex densa). Photo courtesy of Neal Kramer, Copyright © 2008.

Coast sedge
(Carex obnupta)
Native

Coast sedge (Carex obnupta) with drooping inflorescence at Sonoma Coast State Beach 2010 May 10. Photo by D. Immel-Jeffery.

Rushes

Toad rush
(Juncus bufonius)
Native

Toad rush (Juncus bufonius). Kristian Peters, Wikimedia Commons.

Spreading Rush, California gray rush
(Juncus patens)
Native

Spreading Rush (Juncus patens) at Golden Gate National Recreation Area in Marin County. Photo courtesy of Robert Steers © 2010 National Park Service.

Brownhead rush
(Juncus phaeocephalus)
Native

Brownhead rush flowers at Point Reyes National Seashore. Photo courtesy of Robert Steer © 2010 National Park Service.