Burke: Viola arvensis vs. Viola trinervata

	Viola arvensis	Viola trinervata
	European field pansy	desert pansy, 3-nerved violet, sagebrush violet
Habit	Puberulent, freely-branched annual, 1-3 dm. tall.	Glabrous, somewhat glaucous perennial from short, thick, very deep-seated rhizomes, the stems several, naked below, 5-15 cm. tall.
Leaves	Leaf blades ovate to lanceolate, coarsely round-toothed, 1-3 cm. long, about equaling the petioles; stipules very large, laciniate into 5-9 segments, usually with one leaf-like segment nearly as large as the main blade.	Leaf blades palmately lobed or compound, the main segments once or twice dissected, the ultimate segments narrowly elliptic, 1.5-4 cm. long; leaves leathery, prominently 3-nerved on the lower surface; petioles longer than the blades.
Flowers	Flowers long-pedunculate, solitary in the leaf axils, whitish or light yellow with a tinge of blue, the spur short; sepals lanceolate, about as long as the petals; style head copiously short-hairy.	Peduncles exceeding the leaves; flowers about 1.5 cm. long, usually bicolored, the upper pair deep reddish-violet, the lower 3 pale to deep lilac, with yellowish or whitish base and purple penciling, occasionally all white or all deep purple; style head hairy.
Fruits	Fruit a 3-valved capsule, ovary superior, placentation parieta	Fruit a 3-valved capsule, ovary superior, placentation parietal.

	Viola arvensis	Viola trinervata
Flowering time	March-June	March-June
Habitat	Fields, roadsides, wastelots, and other disturbed areas where escaping from cultivation.	Sagebrush flats and rocky hillsides, often on lithosol, where vernally moist.
Distribution	Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east across most of North America to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]	Occurring east of the Cascades crest in Washington; north-central Washington to southeastern Oregon. [WildflowerSearch map] [BONAP county map]
Origin	Introduced from Europe	Native
Conservation status	Not of concern	Not of concern
Sibling taxa	V. adunca, V. canadensis, V. flettii, V. glabella, V. howellii, V. lanceolata, V. langsdorffii, V. macloskeyi, V. nephrophylla, V. nuttallii, V. odorata, V. orbiculata, V. palustris, V. pluviae, V. purpurea, V. renifolia, V. riviniana, V. selkirkii, V. sempervirens, V. sheltonii, V. sororia, V. tricolor, V. trinervata, V. ×wittrockiana	V. adunca, V. arvensis, V. canadensis, V. flettii, V. glabella, V. howellii, V. lanceolata, V. langsdorffii, V. macloskeyi, V. nephrophylla, V. nuttallii, V. odorata, V. orbiculata, V. palustris, V. pluviae, V. purpurea, V. renifolia, V. riviniana, V. selkirkii, V. sempervirens, V. sheltonii, V. sororia, V. tricolor, V. ×wittrockiana
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: OR, WA Local Web sites: Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Viola trinervata

European field pansy

desert pansy, 3-nerved violet, sagebrush violet

Habit

Puberulent, freely-branched annual, 1-3 dm. tall.

Glabrous, somewhat glaucous perennial from short, thick, very deep-seated rhizomes, the stems several, naked below, 5-15 cm. tall.

Leaves

Leaf blades ovate to lanceolate, coarsely round-toothed, 1-3 cm. long, about equaling the petioles;

stipules very large, laciniate into 5-9 segments, usually with one leaf-like segment nearly as large as the main blade.

Leaf blades palmately lobed or compound, the main segments once or twice dissected, the ultimate segments narrowly elliptic, 1.5-4 cm. long;

leaves leathery, prominently 3-nerved on the lower surface;

petioles longer than the blades.

Flowers

Flowers long-pedunculate, solitary in the leaf axils, whitish or light yellow with a tinge of blue, the spur short;

sepals lanceolate, about as long as the petals;

style head copiously short-hairy.

Peduncles exceeding the leaves;

flowers about 1.5 cm. long, usually bicolored, the upper pair deep reddish-violet, the lower 3 pale to deep lilac, with yellowish or whitish base and purple penciling, occasionally all white or all deep purple;

style head hairy.

Fruits

Fruit a 3-valved capsule, ovary superior, placentation parieta

Fruit a 3-valved capsule, ovary superior, placentation parietal.