This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Glabrous; rootstock vertical, often stout and much branching; leaves at petaliferous flowering about 3' high, the blades about 1' wide, broadly ovate, cordate, slightly acuminate with obtuse apex; aestival leaves 2'-3' wide, reniform, abruptly acuminate, the base cordate to truncate-decurrent, crenate-serrate; scapes somewhat exceeding the leaves; petals violet, the upper obovate, the lateral spatulate with clavate beard, the spur petal slightly hairy; sepals lanceolate, white margined; cleistogamous flowers ovoid, on erect peduncles becoming 4'-5' long in fruit; capsules ellipsoid, green, 6" long; seeds brown, 1" long.
Low shady groves, central Kansas, and along streams in the foothills of eastern Colorado. May-June.
Viola cucullata Ait. Hort. Kew. 3: 228. 1789.
Glabrous; leaves except the earliest broadly ovate to reniform, cordate, acute or subacuminate, finely crenate-serrate, often 3 1/2' wide when mature; peduncles usually much exceeding the leaves; corolla violet-blue, darker colored at the throat, sometimes white; lateral petals with strongly clavate beard, spurred petal glabrous, generally somewhat shorter than the lateral; sepals narrowly lanceolate; cleistogamous flowers long and slender, on erect, often elongate peduncles; capsules ovoid-cylindric, green, 5"-7 1/2" long, but little exceeding the long-auricled sepals; seeds nearly black, 3" long.
Viola viarum Pollard in Britton, Man. 635. 1901.
Glabrous; leaves broadly deltoid with the basal angles rounded; some undivided, merely crenate-serrate, or with a few slight incisions; others pe-dately 3-7-lobed or -parted, the middle segment broad acute serrate, the lower segments commonly lunate with outer margin sinuately serrate; corolla deep violet, the spurred petal glabrous narrow emar-ginate, the lateral pair narrow, bearing a sparse short clavate beard, the upper pair broader divergent emarginate; sepals narrowly lanceolate, with rather short auricles; cleistogamous fruit on peduncles somewhat shorter than the petioles; ripe capsules pale green, ovoid-cylindric; seeds olive-brown, nearly 1" long.