Nuttall’s or Nuttall’s yellow or yellow prairie violet, violette de Nuttall Nuttall’s or Nuttall’s yellow or yellow prairie violet, violette de Nuttall

Crocion nuttallii (Pursh) Nieuwland & Lunell

Plants perennial, caulescent, not stoloniferous, 2–27 cm. Stems 1–6, ascending to erect, leafy proximally and distally, ca. 1/2 subterranean, puberulent, on caudex from usually vertical, subligneous rhizome. Leaves basal and cauline; basal: 1–6; stipules adnate to petiole, forming 2 linear-lanceolate wings, margins entire, apex of each wing free, acute, few-toothed or lobed; petiole 2–17 cm, glabrous or minutely puberulent; blade lanceolate, ovate, or elliptic, 1–9 × 0.6–2.5 cm, base attenuate, margins entire or serrulate, sometimes sinuate, ciliate, apex acute to obtuse, mucronulate, surfaces glabrous or puberulent; cauline similar to basal except: stipules adnate to or free from petiole, linear to linear-lanceolate or linear-oblong, sometimes leaflike, margins usually entire, rarely laciniate or glandular, apex acute to acuminate; petiole 2–7 cm; blade 1.4–7.2(–10) × 1.1–2.3 cm, length 1.3–4.4 times width, apex acute. Peduncles 3–13 cm, glabrous or puberulent. Flowers: sepals linear-lanceolate, margins eciliate, auricles 0.5–1 mm; petals deep lemon-yellow adaxially or on both surfaces, upper 2 often brownish purple abaxially, lower 3 dark brown- to brownish purple-veined, lateral 2 sparsely bearded, lowest 6–13 mm, spur yellow, gibbous, 0.5–1.5 mm; style head bearded; cleistogamous flowers axillary. Capsules subglobose to ovoid, 4–10 mm, usually glabrous, rarely finely puberulent. Seeds medium brown, 2–3.2 mm, elaiosome extending over 1/3 length of seed and completely covering funiculus. 2n = 24.

Flowering Apr–Jun. Sagebrush flats, prairie grasslands, dry stream banks, juniper woodlands, scree slopes; 400–2600 m; Alta., Man., Sask.; Ariz., Colo., Idaho, Kans., Minn., Mont., Nebr., N.Mex., N.Dak., S.Dak., Utah, Wyo.

D. M. Fabijan et al. (1987) stated that Viola nuttallii showed no evidence of hybridization even when growing with V. vallicola east of the Rocky Mountains.