The grasses that supply the voles' food and cover are mostly _Poa_ (the bluegrasses) and _Bromus_ (bromegrass, chess, or cheat). _Poa pratensis_ is a common lawn and pasture grass, _P. annua_ is a weed species. The bluegrasses begin to grow in late winter about Lawrence, Kansas, and they remain green until late in the fall. During this time, the voles eat the blades and heads of bluegrass, and make their runways under the culms. The prairie voles utilize several species of _Bromus_. _Bromus inermis_ and _B. carinatus_ are important range and pasture grasses, but _japonicus_ is a weed of little or no economic value. These are soft, tender grasses, but, in contrast to the bluegrasses, they become dry in midsummer, and are then unsuitable as food. However, they continue to form a protection over the runways of the voles. The legumes, which appeared to be most important to the prairie vole, are clover (_Trifolium_ spp. and _Melilotus alba_) and alfalfa (_Medicago sativa_). These plants are common in both cultivated and feral states. They form a different type of cover from that made by grasses. Voles, living in clover and alfalfa, do not make runways as distinct as they do in grasslands. The clover and alfalfa plants are branched and of a spreading growth form, whereas the grasses have leaves which are appressed to the main stem. The individual grass plants grow close together, and a vole cannot run through grass without trampling some of it. As voles use the same paths repeatedly, the grass in their runs becomes flattened and dies. There is sufficient room between the stems of the clover and alfalfa plants to allow the voles to pass through without treading on the stems. In such a habitat, vole runways are poorly developed, and are difficult to find. Voles in grasslands feed in runways, as attested by the piles of cuttings found in the runways and the nibbled grass which borders them. Voles in clover or alfalfa feed at the bases of the plants wherever the plants may grow. In the latter type of cover the cuttings are rather evenly distributed. Compositae formed a minor part of the cover in most of the habitats studied. Many grasslands have a stand of dandelions; sow thistle, wild lettuce, and ragweed were also common in some grasslands. The voles ate the leaves and sometimes the seeds and underground parts of these plants. TABLE 3. _Plants Used for Food by the Prairie Vole_ Graminae _Poa annua_ _P. compressa_ _P. pratensis_ _Bromus inermis_ _B. carinatus_ _B. japonicus_ _Andropogon furcatus_ _Agropyron repens_ _Setaria lutescens_ _S. viridis_ Leguminosae _Melilotus alba_ _Medicago sativa_ _Trifolium_ spp. _Gymnocladus dioica_ Solanaceae _Solanum carolinense_ Boraginaceae _Galium aparine_ Caprifoliaceae _Lonicera japonica_ Compositae _Lactuca scariola_ _Sonchus arvensis_ _Ambrosia trifida_ _A. artemisiifolia_ _Taraxacum officinale_ ASSOCIATES