Montana Field Guide

PLANTS: Perennial herbs that lack a central stem (acaulescent) where the flower peduncle and the leaf petiole grow directly from a thick, fleshy rhizome. Plants are sparsely pubescent and 5-30 cm tall. Sources: Lesica et al. 2012; Little in Flora of North America [FNA] 2015.

LEAVES: Basal, 1-5 in number, with petioles, and prostrate to ascending. Petioles are 3-10 cm and hairy (pubescent). Blades are simple (not lobed), reniform (broader than long) with crenulate margins, 2-6 cm wide. Surfaces are sparsely to densely pubescent. Stipules are lanceolate. Sources: Lesica et al. 2012; Little in FNA 2015.

INFLORESCENCE: A single, white flower that is scapose and arises from a rhizome. Peduncles are 5-8 cm long, puberulent. Flowers are 10-15 mm long. Sepals are 5 in number, separate, usually not ciliate, and lanceolate to ovate in shape with 1-2 mm long auricles. Petals are 5 in number, separate, beardless, and white. The upper 2 petals are erect. The lower 3 petals spread and are purple-veined; lowest petal is 8-10 mm. The sac-like spur is colored the same as the petals, swollen on one side (gibbous), and 1-2 mm long. Fruit is a capsule. Sources: Lesica et al. 2012; Little in FNA 2015.

Viola is the Latin name for the plant, derived from the Greek word ion for 'violet' (Little in FNA 2015; Giblin et al. [eds.] 2018).

Flowering from June to July in Montana; across its range from April through June (Little in FNA 2015).

Viola species exhibit great phenotypic variation. Leaf and stem sizes usually increase a lot between early spring and late summer (Little in FNA 2015). Stem, leaf, and flower sizes vary with environmental factors, such as aspect, light, soil moisture, and other soil properties (Little in FNA 2015).

Montana has about 3 Viola species that lack central stems (acaulescent), have simple leaf blades, and have whitish flowers:

Kidney-leaf White Violet - Viola renifolia
*Petioles-Peduncles: Peduncles are shorter than the leaves (petiole and blade);
*Leaves: Wider than long, and pubescent on the underside;
*Flowers: Cleistogamous flowers on prostrate to ascending stems are present;
*Petals: White with purple veins on the lower 3;
*Style: Beardless;and,
*Roots: Rhizomes present.

Smooth White Violet - Viola macloskeyi
*Leaves: No wider than long, and glabrous on both surfaces;
*Flowers: Cleistogamous flowers on ascending stems are present;
*Petals: White with purple veins on the lower three;
*Style: Beardless;and,
*Roots: Rhizomes and stolons are present.

Marsh Violet - Viola palustris
*Leaves: Orbicular-cordate in shape with crenate margins;
*Flowers: Cleistogamous flowers on ascending stems are present;
*Petals: White to bluish with purple veins on the lower 3. The back tinged with blue;
*Style: Beardless;and,
*Roots: Rhizomes and stolons are present.

Swampy or boggy soil in forests in the montane zone.

POLLINATORS
Pollinators to Violets (Viola spp.) are rewarded with nectar and pollen and include bumblebees, honeybees, solitary bees, syrphid flies, butterflies, skippers, hawkmoths, moths, and beeflies (Little in FNA 2015). The following Bombus species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans, Bombus pensylvanicus, Bombus bimaculatus, Bombus griseocollis, and Bombus impatiens (Colla and Dumesh 2010, Williams et al. 2014). Thrips (Order Thysanoptera), aphids, and other tiny insects with pollen on their bodies have been observed in the flowers of Violets and potentially could affect pollination (Little in FNA 2015).

Plants reproduce from seeds and rhizomes.

FLOWERS [Adapted from Lesica et al. 2012; Little in FNA 2015]
Stamens are 5. Pistil has 1 style that is beardless. Ovary is superior.

Flowers are cleistogamous, which means they self-pollinate and set a fertile seed without the flower opening. These flowers may be found on prostrate or ascending peduncles.

FRUITS [Adapted from Lesica et al. 2012; Little in FNA 2015]
Capsules are 3-5 mm (Lesica et al. 2012) or 5-8 (Little in FNA 2015) long, ellipsoid, glabrous, and yellow-green. Seeds are beige, mottled to bronze, usually arillate with elaiosome, and 1.5-2.2 mm long.

SEED DISPERSAL [Adapted from Little in FNA 2015]
Violets have capsules that split into three valves, which are usually thick in perennial species such as Prairie Violet, and thin in annual species. Some species have capsules that open relatively slowly to expose the seeds. Other species have capsules that as they dry will cause the valves to contract and squeeze the seeds which ejects them. Violet species that have downward pointing capsules passively release seeds while those on erect peduncles ballistically disperse seeds.

Some species disperse their cleistogamous seeds into the soil or duff.

Most Violet species have a fleshy appendage or covering (aril) on the seed that is oil-rich (elaiosome), which is attractive to ants; thus, seeds are dispersed by ants (myrmecochory).

In Montana threats have not been identified.