Perennial herb 10 - 45 cm tall Leaves: several, both basal and alternate, stalked, soft-hairy or almost hairless, round-toothed, and 4 - 10 cm long. There are one to several somewhat kidney-shaped basal leaves, and near the top of the stem one to four somewhat broad egg-shaped (normally a bit wider than long) leaves with straight or slightly indented bases and short pointed tips. Stipules green, non-toothed, egg-shaped, often widest just above base, and narrowing to a short, somewhat pointed tip. Flowers: in upper leaf axils, slender-stalked, yellow, bilaterally symmetric with two upper petals, two lateral petals, and lower petal with base modified into a rounded nectar spur. In the summer, producing very fertile flowers that do not open (cleistogamous). Sepals: five, green, lance-shaped with ear-like appendages (auricles) at the base. Petals: five, separate, all differently shaped, clear yellow with brownish purple veins near base. The two lateral petals have a beard of hairs near the base, and the lowest petal is prolonged at its base into a short, rounded spur or sac. Stamens: five, separate, but very tightly arranged so anthers touch as they surround ovary. The filaments are very short, and the lower two stamens have spur-like nectaries on their backs that extend into the spur or sac of the lower petal. Pistil: with a single-chambered, superior ovary; and a single hairy-tipped style that enlarges below the head-shaped stigma. Fruit: a many-seeded, 1 - 1.2 cm long, elongate, hairy or hairless capsule that opens lengthwise from top. The seeds are pale brown and have a large amount of oily endosperm, and often an appendage (aril). Stems: one to several, erect, normally soft-hairy (sometimes less hairy), producing both leaves and flowers, and arising from a short, stout, very scaly, yellow rhizome.
Similar species: Viola pubescens is somewhat similar to V. canadensis, but that species has white flowers, stem leaves that are usually longer than wide, and papery, white, more elongate lance-shaped stipules. There are two varieties of V. pubescens that occur in the Chicago Region. The typical variety, V. pubescens var. pubescens, has only one or two stems, densely hairy leaves, no or only one basal leaf, more round-tipped stem leaves with straight or wedge-shaped bases, more than eighteen teeth per leaf side, and more widely egg-shaped upper stipules which narrow rather abruptly into a slender point at the tip. The other variety, V. pubescens var. scabriuscula, usually has at least two stems, mostly hairless leaves, one to three basal leaves, inversely heart-shaped stem leaves (pointed tip and lobed base), only up to eighteen teeth per leaf side, and more elliptic to narrowly egg-shaped upper stipules with a short blunt-point at the tip. A species that has not yet been reported west of Ohio in the Great Lakes, V. hastata, is quite similar to V. pubescens except it has arrowhead-shaped leaves that are much longer than wide, and a tapering, pointed leaf tip.
Flowering: April to June
Habitat and ecology: Common in woodlands and mesophytic savannas or beech forests.
Occurence in the Chicago region: native
Notes: In its typical hairy form, this species has been known in the past under the scientific name Viola pensylvanica. The less hairy form, now known as V. pubescens var. scabriuscula, was known as a separate species, V. eriocarpa.
Etymology: Viola is the classical name for the genus. Pubescens means "downy, short-haired" referring to the typically hairy leaves.
Plants 1-4.5 dm from a short, stout, densely scaly, light brown or yellowish rhizome, softly hairy throughout, varying to essentially glabrous; lvs 2-4 near the top, often accompanied by 1-several long-petiolate, reniform-cordate radical lvs; cauline lvs orbicular- ovate to broadly ovate, short-pointed, crenate-dentate, with cordate or truncate-decurrent base, 4-10 cm, usually a little wider than long; stipules broadly ovate; stem often with 1 or 2 stipule-like sheathing bracts well above the base; fls on slender, axillary peduncles; pet clear yellow with brown-purple veins near the base, the lateral ones bearded; style bearded at the capitate summit; frs 10-12 mm, woolly or glabrous; seeds pale brown; 2n=12. Rich woods, or sometimes in meadows; N.S. to Man. and N.D., s. to S.C., Ga., La., and Tex. Apr.-June. (V. pensylvanica; V. eriocarpa, the more glabrate phase)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.