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.

Myrtle's silverspot is a medium-sized butterfly in the brush foot family (Nymphalidae), an endangered subspecies of the zerene fritillary. It is endemic to California, where it is known from only about four locations just north of the San Francisco Bay Area, including two at Point Reyes National Seashore. Its wingspan is approximately 2.2 inches (56 mm). The upper surfaces of the wings are golden brown with numerous black spots and lines. The undersides are brown, orange and tan with black lines and silver and black spots. Larvae are dark colored with many sharp branching spines on their backs. Myrtle's silverspot is larger and paler than the closely related Behrens' silverspot, which is now limited to the vicinity of Point Arena in Mendocino County. Myrtle's silverspot is also closely related to the Oregon silverspot.