Viola triloba Schwein. - Three-lobed Violet

Viola triloba plant

Family - Violaceae

Stems - Plants acaulescent. Caudex thick, elongated, horizontal, woody, with fleshy roots.

Leaves - Basal. Earliest leaves cordate, acute. Later leaves lobed, sagittate, typically with 5-7 lobes. Petioles to +7cm long, pubescent. Leaf tissue decurrent on petiole for much of it's length but very thin. Blades glabrous above, ciliate below, (especially near base), shallowly serrate to crenate-serrate, +3cm broad and long. Margins typically ciliate.

Viola triloba leaves

Inflorescence - Single long-pedunculate flower arising from caudex. Peduncles glabrous, to +12cm long, exceeding the leaves, curved at apex.

Flowers - Petals 5, violet (rarely white) and with some white at base, with deep purple venation, rounded at apex, -2cm long, 7-8mm broad, generally obovate to oblanceolate. Lateral petals heavily bearded. Upper petals also slightly bearded. All petals glabrous externally. Lowest petal saccate at base, (the sac protruding beyond the sepals). Stamens 5, converging around the pistil, to +4mm long. Lower 2 stamens with appendages. Appendages to 3mm long, green. Anther connective orange, expanding beyond the anther, to 1.5mm long. Anthers pale yellow. Ovary superior, green, glabrous, 3mm long, unilocular, somewhat conic. Ovules many. Style 2mm long, greenish white, glabrous, expanded at apex. Stigma truncate, deltoid. Sepals 5, green with scarious margins, lanceolate, acute, to 8mm long, 3mm broad, glabrous, entire but ciliolate. Lowest two sepals with small auricles. Auricles to 1mm long, ciliolate-margined.

Viola triloba flower

Viola triloba calyx

Flowering - April - May.

Habitat - Dry rocky open woods, thickets, bluffs.

Origin - Native to U.S.

Other info. - V. triloba is just one of the many small purple-flowered violets you are sure to encounter in the Missouri woods. When young, this plant is difficult to tell apart from other violets, such as V. sororia, but as the plant mature its leaves will become lobed. V. triloba is found mostly in the lower half of the state and prefers acidic soils.

Photographs taken at Rock Bridge State Park, Columbia, MO., 4-17-04.


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