Viola pallens (Banks ex Ging.) Brainerd

Smooth White Violet

© SRTurner

Family - Violaceae

Habit - Perennial forb, to 10 cm tall, with a prostrate to ascending rhizome 1-2 mm thick, also producing threadlike stolons at fruiting.

Stem - Aerial stems absent.

Leaves - In a basal rosette, long-petiolate, the petiole glabrous or hairy. Stipules inconspicuous, membranous, free from the petiole, narrowly lanceolate, the margins entire, glandular-hairy. Leaf blades 0.8-3.7 cm long, mostly wider than to about as wide as long, broadly ovate to nearly circular, all unlobed, rounded or broadly and bluntly pointed at the tip, cordate at the base, the margins finely toothed or scalloped to occasionally nearly entire, the surfaces glabrous.

	Leaves.
© SRTurner

	Leaf adaxial.
© SRTurner

	Leaf abaxial.
© SRTurner

Inflorescences - Solitary flowers, on stalks not or only slightly overtopping the leaves, arising directly from rhizome. Stalks of cleistogamous flowers often relatively short, erect or strongly ascending.

Flowers - Sepals 3-4 mm long, lanceolate, angled to a sharply pointed tip, the margins glabrous, the basal auricles short and inconspicuous. Corollas 6-10 mm long (except in cleistogamous flowers), the petals oriented more or less forward in life but curved or arched outward or backward toward their tips, longer than the sepals, white (with a greenish white throat), the lower petal usually with dark purple or brownish purple veins toward the base, the lateral and lower petals not noticeably bearded, the upper surface glabrous or nearly so, the spur conspicuous, well-exserted beyond the sepal auricles, stout and often somewhat hemispheric in shape. Stamens not or only slightly exserted, often not visible without dissection of the flower. Style slender, slightly expanded into a narrow, more or less scoop-shaped, hollow, truncate tip. Cleistogamous flowers produced.

	Flower.
© SRTurner

	Flower.
© SRTurner

	Corolla and throat.
© SRTurner

Fruits - Capsules 4-6 mm long, narrowly ellipsoid, green, drying to tan, the surface glabrous. Seeds 1.0-1.4 mm long, black.

Flowering - April - May.

Habitat - Sheltered bases and ledges of bluffs and banks of streams; on sandstone substrate.

Origin - Native to the U.S.

Lookalikes - Broadly, V. striata.

Other info. - This diminutive white violet is rare in Missouri, known from only a few locations in a single county. It is much more common in regions to our north and northwest. Once found it is easily recognized by its habitat, lack of a stem, nearly round leaves, and small, white, violet-patterned flowers.

This species is usually considered a glacial relict from the Pleistocene, when Missouri's climate was cooler and wetter. It persists now only in sheltered microhabitats which preserve some degree of the plant's cool, moist habitat preference.

Photographs taken at Pickle Springs Natural Area, Ste. Genevieve County, MO, 5-11-2020 (SRTurner).