Montana Field Guide

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

LEAVES: Basal, 2-11 in number, with petioles, and are ascending to erect. Petioles are 3-16 cm and hairy (pubescent). Blades are deeply dissected with 5-9 lobes and ciliate, smooth (entire) margins. Surfaces are pubescent, though sometimes only on the veins. Lobes vary in shape - lanceolate, spatulate, falcate, or linear, 1-7cm wide by 2-8 cm long. Base of the blade is truncate to reniform. Apex of the blade is acute to obtuse. Stipules are linear lanceolate with entire margins and an acute apex. Source: Little in FNA 2015.

INFLORESCENCE: A single, violet flower that is scapose and arises from a rhizome. Peduncles are 5-18 cm long, glabrous or pubescent. Sepals are 5 in number, separate, mostly 6-8 mm long, usually ciliate, and lanceolate to ovate in shape with 1-2 mm long auricles. Petals are 5 in number, separate, 10-20 mm long, and violet or reddish-violet. The upper 2 petals are erect, less strongly dark veined, and usually bearded. The lower 3 petals spread and are white at their base with dark violet veins; the lowest petal is bearded, 10-25 mm long. The sac-like spur is colored the same as the petals, swollen on one side (gibbous), and 2-3 mm long. Fruit is a capsule. Sources: McGregor et al. [eds.] 1986; 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 March 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). The depth of the lobes can be dependent upon the age of the plant (Little in FNA 2015). Hybridization among the blue-flowered, acaulescent Violets in eastern North America is well documented (Little in FNA 2015).

Prairie Violet - Viola pedatifida
Separated by having this combination of characteristics:
*Petioles-Peduncles: Peduncles about equal to or usually longer than the leaves (petiole and blade);
*Leaves: Deeply lobed with lobes being similar in width and shape;
*Flowers: Cleistogamous flowers are present;
*Style: Beardless; and
*Petals: Lateral petals are bearded and sometimes the lowest one.

Prairies, grasslands, disturbed ground, and gravelly hills from 500 to 1,000 meters in elevation (Little in FNA 2015).

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 and longer than the stamens. Ovary is superior.

Flowers are cleistogamous, which means they self-pollinate and set a fertile seed without the flower opening. Some acaulescent, blue-flowered Violet species develop their cleistogamous flowers beneath the soil surface or in the duff and arise on peduncles as they mature.

FRUITS [Adapted from Little in FNA 2015]
Capsules are 10-15 mm long, ellipsoid, glabrous, and yellow-green. Seeds are beige, mottled to bronze, usually arillate with elaiosome, and 1.5-2.5 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 ballisticly 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 intrinsic threats include small populations that are widely scattered.

STATE THREAT SCORE REASON
A State Threat Score is not assigned because the scope, severity, and/or timing of threats have not been documented (MTNHP Threat Assessment 2021).