Misidentifying violets is easy; we have done it here more than once. There are several similar white violets in our area, but this species should be easy to identify if we look for a combination of three things: bearded side petals (see the enlargement above), leafy flower stems (in some other species the flowers rise directly from the base with no leaves on the flower stems), and roundish toothed leaves (see the picture below; the leaves of Canada Violet, for example, are more elongated).
Gray (with help from his successors) describes the genus and the species:
VtOLA [Tourn.] L. VIOLET. HEART’S-EASE. Revised By E. Brainerd. Petals somewhat unequal, the lower one spurred at the base. Stamens closely surrounding the ovary, often slightly cohering with each other; the two lower bearing spurs which project into the spur of the corolla. Besides these conspicuous blossoms, which appear in spring, others are produced later, on shorter peduncles or on runners, often concealed under the leaves; these never open nor develop petals, but are fertilized in the bud and are far more fruitful than the ordinary blossoms. —The closely allied species of the same section, when growing together, often hybridize with each other, producing forms that are confusing to the student not familiar with the specific types. The hybrids commonly display characters more or less intermediate between those of the parents, and show marked vegetative vigor but greatly impaired fertility. (The ancient Latin name of the genus.)
Plants with leafy stems.
Style not capitate, slender; length of spur at least twice its width; stipules fringed-toothed, somewhat herbaceous.
Tip of the style bent downward, slightly pubescent near the summit; lateral petals bearded; spur less than 8 mm long.
Petals white or cream-colored.
V. striata Ait. Usually 16-30 cm. high when in flower, often in late summer 6 dm. high, glabrous or nearly so; leaves heart-shaped, finely crenate-serrate, often acute; stipules large, oblong-lanceolate; spur rather thick, shorter than the petals; sepals ciliate, narrow, attenuate; capsules ovoid, glabrous, 4-6 mm. long; seeds light brown. — Low or shady ground, Ct. to Minn., and southw.
We find these charming yellow violets on moist wooded hillsides; these grew near the Trillium Trail in Fox Chapel.
Gray lists this as Viola scabriuscula; others as V. pubescens var. scabriuscula or V. eriocarpa. From Gray’s Manual of Botany: V. scabriuscula Schwein. (SMOOTH YELLOW V.) Similar to the preceding [V. pubescens], with which it intergrades ; the more pronounced forms have commonly 2-4 stems and 1-3 radical leaves from one rootstock, the stems shorter and more leafy, the leaves smaller and sparingly pubescent to glabrate, the time of flowering earlier ; flowers, capsules, and seeds as in the preceding [petals purple-veined, the lateral bearded ; sepals narrowly lanceolate, acute ; apetalous flowers abundant in summer on short peduncles ; capsules ovoid, glabrous or woolly ; seeds light brown, large, nearly 3 mm. long]. Moist thickets, often in heavy soil, e. Que. to L. Winnipeg, and southw.
Our most common violets are the violet-colored ones, but these white ones are often found in open woodlands. These grew in a woodland that was also liberally dotted with common blue violets and a scattering of yellow violets.