Viola adunca is a species of violet known by the common names hookedspur violet, early blue violet, sand violet, and western dog violet. It is native to meadows and forests of western North America, Canada, and the northern contiguous United States.
This is a hairy, compact plant growing from a small rhizome system. The leaves are spade- or heart-shaped, sometimes with broadly wavy margins. They are generally 1 to 4 centimeters long. The single-flowered inflorescence grows at the end of a long, very thin peduncle. The nodding flower is a violet with five purple petals, the lower three with white bases and purple veining. The two side petals are white-bearded near the throat. The upper two petals may have hooked spurs at their tips.
There are several varieties of V. adunca; a white-petaled form has been noted in Yosemite National Park.
- Sullivan, Steven. K. (2015). "Viola adunca". Wildflower Search. Retrieved 2015-04-23.
- "Viola adunca". PLANTS Database. United States Department of Agriculture; Natural Resources Conservation Service. 2015. Retrieved 2015-04-23.
- Giblin, David (Editor) (2015). "Viola adunca". WTU Herbarium Image Collection. Burke Museum, University of Washington. Retrieved 2015-04-23.
- "Viola adunca". Jepson Flora Project: Jepson Interchange. Jepson Herbarium; University of California, Berkeley. 1993. Retrieved 2015-04-23.