Montana Field Guide

Stem 20–40 cm. Leaf blades 1–2 mm wide. Bracts 1–7 cm long. Flowers 1 or 2; sepals 15–45 mm long, marked with purple; petals greenish to purplish, 3–5 cm long; inner surface with a yellow-fringed, crescent-shaped gland extending the width of the petal, purple above and below; anthers apiculate. Capsule spindle-shaped, erect, 2–5 cm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Our plants are variety gunnisonii.

Gunnison's Mariposa Lily - Calochortus gunnisonii
*Basal Leaf: Channeled, similar in width, but shorter than stem leaves.
*Anthers: Apiculate (short, sharp tip).
*Sepals: Usually shorter than petals.
*Petals: White or yellowish to purple; greenish inside and sometimes purple-banded or -spotted next to gland. Green stripe absent on the outside. Tip not acuminate.

Bruneau Mariposa Lily - Calochortus bruneaunis, SOC
*Basal Leaf: Channeled, similar in width, but shorter than stem leaves.
*Anthers: Oblong.
*Sepals: Usually shorter than petals.
*Petals: White. Green striped on the outside. Nearly hairless on the inside (glabrate) near gland. Tip apiculate.

Nuttall's Mariposa Lily - Calochortus nuttallii
*Basal Leaf: Channeled, similar in width, but shorter than stem leaves.
*Anthers: Oblong.
*Sepals: Longer or shorter than petals.
*Petals: White to purple tinged, yellow at the base. Lacking a green stripe on the outside. Bearded on the inside, adjacent to gland. Tip apiculate.

Green-band Mariposa Lily - Calochortus macrocarpus
*Basal Leaf: Channeled, similar in width, but shorter than stem leaves.
*Anthers: Lanceoloid (round in cross-section; wider from base to below middle then tapering to the tip).
*Sepals: Usually longer than petals.
*Petals: Purple. Green striped on the outside. Tip acuminate.

The following Mariposa Lilies differ from those above in that their basal leaves are flat, much wider than the stem leaves, and often more than half as long as the stem leaves:

Baker Mariposa Lily - Calochortus apiculatus
Elegant Mariposa Lily - Calochortus elegans
Big-pod Mariposa Lily - Calochortus eurycarpus

Usually calcareous soil of grasslands, sagebrush steppe, woodlands, open forest; valleys, montane (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).