Taxon Report

Calochortus clavatus Wats. var. avius Jeps.

Pleasant Valley mariposa-lily

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© 2023 Sierra Pacific Industries

Taxon Summary

Calochortus clavatus var. avius, commonly known as Pleasant Valley mariposa-lily, is a perennial bulbiferous herb in the Liliaceae that is found only in California. It occurs within Lower montane coniferous forest (Josephine silt loam, and volcanic), growing at elevations from 305 to 1800 meters. Calochortus clavatus var. avius is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.


  Classification

Scientific Name:
Calochortus clavatus Wats. var. avius Jeps.
Common Name:
Pleasant Valley mariposa-lily
Family: Liliaceae
Element Code: PMLIL0D095
USDA Plants Symbol: CACLA
Synonyms/Other Names:

Ecology and Life History

Lifeform: perennial bulbiferous herb
Blooming Period: May-Jul May-Jul
Elevation: 305-1800 (1000-5905)
General Habitats: Lower montane coniferous forest
Microhabitat:
Microhabitat Details:

Occurrence Data from the CNDDB

Total Occurrences: 131
Element Occurrence Ranks:
   Excellent (A) 7
   Good (B) 37
   Fair (C) 19
   Poor (D) 6
   None (X) 1
   Unknown (U) 61
California Endemic:  True
California Counties and Islands: Name (Code)
Amador (AMA), Calaveras (CAL), El Dorado (ELD), Mariposa (MPA)*, Placer (PLA)
Quads: Name (Quad Code)
Caldor (3812054), Camino (3812066), Devil Peak (3812085), Devils Nose (3812044), Dorrington (3812033), Garnet Hill (3812043), Illinois Hill (3712031)*, Kyburz (3812073), Omo Ranch (3812055), Peddler Hill (3812053), Pollock Pines (3812075), Riverton (3812074), Sly Park (3812065), Stump Spring, Calif. (3812064)

Threat List Data from the CNDDB

Threat List Total: 17
EOs with Threat Listed: Total EOs % of EOs
104 79 %
Logging 91 69%
Road/trail construction/maint. 35 26%
Grazing 30 22%
Erosion/runoff 14 10%
ORV activity 10 7%
Other 10 7%
Biocides 9 6%
Over-collecting/poaching 6 4%
Wood cutting or brush clearing 6 4%
Non-native plant impacts 5 3%
Foot traffic/trampling 5 3%
Improper burning regime 5 3%
Development 3 2%
Agriculture 3 2%
Recreational use (non-ORV) 2 1%
Mining 2 1%
Vandalism/dumping/litter 1 0%

Notes

Threatened by development and logging, and possibly by horticultural collecting. Potentially threatened by pipeline construction. 508B (Old Iron Mountain) former quad name is Stump Spring, CA.
Threats:
Taxonomy:
Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 5 February 2025].