Whitegrass is a native, perennial, warm-season grass growing from 12 to 36 inches high (but sometimes to 55+ inches) with stems that are weak but usually erect, but if recumbent, they may root at the nodes. Stems are mostly smooth but the nodes may be hairy.
Leaves: Blades are 3 to 7 inches long (6-17 cm) and 6-11 mm wide, droopy, usually smooth on top and hairy under. The drooping leaves have tiny teeth on the edges which can easily tear clothing and cut flesh, hence the alternate common name "cutgrass". The leaf sheaths are mostly smooth, dull green, usually without hair. Ligules are 1 to 3 mm long. The leaf mid-vein is prominent but not shiny as in the similar looking Japanese Stilt Grass (Microstegium vimineum)
Inflorescence: Flowering heads form in an open panicle, up to 10 inches long with one panicle branch per stem node. Branches are wiry. The heads are usually fully emerged from the leaf sheaths, unlike Rice Cutgrass.
Flowering: Spikelets in the Leersia genus are considered 'naked', that is, without glumes. Spikelets are 2.5 to 3.6 mm long and overlap. They form a single row and are appressed along the upper part of each branch of the panicle and the lower 1/3 of the branch is free of spikelets. Lemmas may have only a few straight hair on the margins and keels and the lemma body is strongly keeled and either without hair or with very short soft hair. There is only 1 floret per spikelet in the Leersias and this species has 2 anthers per floret. Florets are somewhat flattened in appearance.
Seed: The seeds look like rice grains and thus are not easily confused with grass seeds of other genus. Mature fruit is reddish-brown.
Habitat: Whitegrass is a warm-season grass found in moist shady places in wooded areas and near streams. It grows from short scaly rhizomes which have a braided appearance. It is palatable to browsers.
Names: The genus, Leersia, is named for 18th Century German botanist Johann Daniel Leers. The species name, virginica refers to the state of Virginia where the species was first described. The author name for the plant classification - ‘Willd.’ refers to Carl Ludwig Willdenow (1765-1812), German botanist, a founder of the study of the geographic distribution of plants. He was director and curator of the Botanic Garden of Berlin.
Comparison: The other species of cutgrass that is similar is Rice Cutgrass, L. oryzoides. Compared to Rice Cutgrass, Whitegrass leaves are narrower, shorter, less sharp, and flowering heads are shorter. The heads are usually fully emerged from the leaf sheaths, unlike Rice Cutgrass. The lower flowering branches are solitary whereas Rice Cutgrass may have several branches per node. The spikelets are smaller than Rice Cutgrass and also overlap whereas Rice Cutgrass spikelets barely overlap.
Above: The inflorescence. Note that the lower 1/3 of the panicle branches are free of spikelets. Photos ©Phoebe Waugh, taken in the Upland Garden near the Curator's office.
Below: The spikelets form a single row, overlap, and are appressed along the panicle branch. They are without glumes and have two anthers.
Below: Details of the spikelet and lemmas. Note that spikelets have only one floret, no glumes. Lemmas are keeled and usually with fine hair on the keel and margins. Photos ©Anna Gardner, University of Iowa.
Below: Drawing courtesy USDA-NRCS PLANTS Database / Hitchcock, A.S. (rev. A. Chase). 1950. Manual of the grasses of the United States. USDA Miscellaneous Publication No. 200. Washington, DC.
Below: 1st and 2nd photos - Detail of the leaf sheath and ligule. This example has some fine hair on sheath edge. 3rd photo - detail of stem node, this example with hair.
Below: 1st photo - the upper surface of the leaf blade - forming a deep V before flattening out. 2nd photo - blade underside with the prominent center keel.
Whitegrass. This native perennial is found in the United States from the great plains to the east coast and thus has a more restricted distribution than the other Leersia in the Garden - Rice Cutgrass. Likewise in Minnesota, distribution is more restricted than for Rice Cutgrass. L. virginica is found almost exclusively in the SE quadrant of the state up to and including the metro area. It can be found in many areas along the paths of the Upland Garden.
Three species of Leersia are found in Minnesota - L. lenticularis, Catchfly Grass; L. oryzoides, Rice Cutgrass; and L. virginica, Whitegrass. The first is very limited to 3 counties in the SE corner of the state and is on the State Threatened Species List.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"