Flower:

Single irregular 5-petaled flower at the end of a slender stalk at the top of the stem and arising from the leaf axils. Flowers are yellow, up to ½ inch (≤ 13 mm) long. The upper two petals are erect or bent back, the two lateral petals have short hairs at the base (bearded), the lower petal is hairless, has purple veins near the base, and forms a short rounded spur at the back. The 5 sepals around the base of the flower are minutely hairy, fringed around the edges, the two lower largest, lance-linear to lance-shaped, blunt to pointed at the tip, and have a short extension at the base (auricle) that is straight across to rounded along the end and does not elongate in fruit. Flower stalks are hairy.

Leaves and stem:

Typically, there are 2 or 3 alternate leaves on upper 1/3 of the stem and no basal leaves, rarely one. Leaves are broadly egg to kidney-shaped, wedge-shaped to straight across to somewhat heart-shaped at the base, blunt to rounded at the tip, sometimes abruptly narrowed at the tip. Largest leaves are up to 3 inches (75 mm) long, about as wide as long.  Surfaces are hairy, edges are toothed and fringed with short hairs, leaf stalks are hairy. At the base of the leaf stalk is a leafy appendage (stipule) that is broadly egg-shaped and wedge-shaped at the base. Stems are single from the base, ascending to erect, and covered with spreading hairs. No stolons are produced.

Fruit:

Both petalled (chasmogamous) and petal-less, self-pollinating (cleistogamous) flowers produce fruit, in an ovoid capsule that becomes erect just before splitting into 3 sections and releasing its seed. Chasmogamous flowers bloom in spring, cleistogamous flowers are produced all summer. All capsules are green drying tan or brown, hairless to densely hairy, up to ~½ inch (7 to 14 mm) long. Seeds are medium orange-brown, up to 3 mm long.

Notes:

Downy Yellow Violet was once considered ubiquitous in woodlands across Minnesota, but a major overhaul of Viola accounts published in 2023 has split up V. pubescens, making Viola eriocarpa (Smooth Yellow Violet) the dominant yellow woodland violet here. V. pubescens is still present, but its numbers are few and is more common in Wisconsin.

V. pubescens is recognized by: usually hairy all over, stems single from the base, usually with only 2 or 3 alternate leaves all clustered near the tip, no basal leaves (rarely 1); egg to kidney-shaped leaves, not strongly heart-shaped at the base, usually blunt to rounded at the tip; stipules wedge-shaped at the base; yellow flowers, lateral petals bearded; green capsules, orange-brown seeds.

While V. pubescens is pretty consistent in most characteristics, V. eriocarpa is much more variable: hairy or not, stems single or multiple from the base, 1 to 3 basal leaves, usually 4 or 5 stem leaves on the upper half to 4/5 of the stem, though the lower nodes are sometimes leafless, more consistently heart-shaped leaves, stipules are usually asymmetric at the base. In the case where a plant has a single stem with leaves all near the tip, look on the lower stem for a stipule without a leaf. That would be a sign of V. eriocarpa rather than V. pubescens.

The third yellow violet in Minnesota is Viola nuttallii (Yellow Prairie Violet), which is a rare species only present in a few locations in our western counties. Its leaves are narrowly lance-shaped and toothless, and it lives in open prairies, not woodlands.