Viola palmata, Blue Palmate-leaved Violet Uncommon native, Piedmont & coastal plain Leaves divided into wider segments; may also have some undivided leaves.
Leaves not divided, blue/purple flowers, lacking leafy stems:
Viola cucullata, Blue Marsh Violet Native, Piedmont & coastal plain Hairless, found in wet places, flowers usually darker in the center.
Viola sagittata, Blue Arrowleaf Violet Native, Piedmont & coastal plain Leaves arrow-shaped, triangular, with a few hairs.
Viola fimbriatula, Blue Fringed Violet Native, Piedmont & coastal plain Leaves arrow-shaped, hairy on both sides.
Viola hirsutula, Southern Blue Wood Violet Native, Piedmont only Flowers reddish-purple; leaves "silvery-hairy and somewhat mottled above, often with purple veins."
Viola odorata, Sweet Violet Non-native, Piedmont only Flowers scented; style hooked; spreading by runners.
Viola sororia, Common Blue Violet Native, Piedmont & coastal plain May be hairy or hairless (formerly considered separate species.)
I would probably call any stemless blue/purple violet in Delaware Viola sororia if it wasn't clearly one of the five above.
The pale form is the "confederate violet."
Seven are plants with leaves and flowers on upright stems:
Four have yellow or white flowers on leafy stems:
Viola pubescens var. pubescens, Downy Yellow Violet Native, Piedmont & coastal plain The whole plant is covered with short hairs. Rare on the coastal plain.