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Montana Field Guides

Big-pod Mariposa Lily - Calochortus eurycarpus

Native Species

Global Rank: G4
State Rank: S3S4
(see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value:

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State Rank Reason (see State Rank above)
Numerous recent reports from 7 counties. Tends to grow at high elevations, where its habitat is probably secure.
 
General Description
Stem 15–60 cm. Leaf blade linear to linear-lanceolate, 2–10 mm wide. Bracts 1–4 cm long. Flowers 1 to 3; sepals yellowish, 15–30 mm long; petals white or purplish, 3–4 cm long; inner surface sparsely hairy with a purple, flattened-hemispheric mark 4–6 mm above the fringed bullet-shaped gland; anthers oblong. Capsule ellipsoid, erect, 2–3 cm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Diagnostic Characteristics
Big-pod Mariposa Lily - Calochortus eurycarpus
*Basal Leaf: Flat, broader and usually more than half as long as the stem leaves.
*Anthers: Oblong and blunt at the tip.
*Sepals: yellowish, 15-30 mm long.
*Petals: Outside is white or purplish, 3-4 cm long. Inside is purplish with sparse hairs and at the base a fringed yellow gland; centrally there is a large circular purplish spot.

Baker Mariposa Lily - Calochortus apiculatus
*Basal Leaf: Flat, broader and usually more than half as long as the stem leaves.
*Anthers: Lanceolate (wider from base to below middle and tapering to the tip) and apiculate (short, sharp tip).
*Sepals: 15-25 mm long.
*Petals: Outside is white, drying yellowish, and serrulate on the margins. Inside the petals are hairy (or strongly bearded), white, and at the base it is yellow with a small (1.5 mm), circular, dark, central gland.

Elegant Mariposa Lily - Calochortus elegans
*Basal Leaf: Flat, broader and usually more than half as long as the stem leaves.
*Sepals: purplish, 10-15 mm long.
*Anthers: Lanceolate (wider from base to below middle and tapering to the tip) and apiculate (short, sharp tip).
*Petals: Strongly clawed. Outside is white. Inside is purple, surface is hairy (ciliate or densely long bearded), and at the base is darker purple crescent-shaped gland.

The following Mariposa Lilies differ from those above in that their basal leaves are channeled (v-shaped), similar in width to the stem leaves, and often less than half the length of the stem leaves:

Gunnison's Mariposa Lily - Calochortus gunnisonii
Bruneau Mariposa Lily - Calochortus bruneaunis, SOC
Nuttall's Mariposa Lily - Calochortus nuttallii
Green-band Mariposa Lily - Calochortus macrocarpus

In addition, Calochortus eurycarpus is easily distinguished from Calochortus bruneaunis and Calochortus nuttallii by the arched, but not circular gland inside the petals and in having broader ovaries and fruits (orbicular to oblong). Calochortus eurycarpus has broader ovaries and fruits (orbicular to oblong) while Calochortus gunnisonii has linear ovaries and fruits.

Range Comments
WA to MT south to NV and WY (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 18

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Most often in subalpine meadows. In Montana, this species decends to the valleys. In either case, it prefers open areas and in Montana, it grows in well-drained soil.

References
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Citation for data on this website:
Big-pod Mariposa Lily — Calochortus eurycarpus.  Montana Field Guide.  .  Retrieved on , from