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Boechera pinzliae

(Rollins) Al-Shehbaz

Pinzl's Rockcress

G1Critically Imperiled (G1G2) Found in 1 roadless area NatureServe Explorer →
G1Critically ImperiledGlobal Rank
High - lowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.128570
Element CodePDBRA06270
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderCapparales
FamilyBrassicaceae
GenusBoechera
Synonyms
Arabis pinzliaeRollins
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Taxonomic Comments
Flora North America vol. 7 (2010) reports that Boechera pinzliae is an apomictic hybrid, that is similar to B. elkoensis and B. platysperma.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2021-10-19
Change Date2021-10-19
Edition Date2021-10-19
Edition AuthorsKnight, T. (rev. Morefield, J./Maybury, K. 5/96), rev. L. Oliver (2003), rev. K. Gravuer (2009), rev. L. Oliver, J. Morefield and K. Lazar (2021)
Threat ImpactHigh - low
Range Extent100-1000 square km (about 40-400 square miles)
Number of Occurrences1 - 5
Rank Reasons
Boechera pinzliae is a narrow alpine endemic, known primarily from the Boundary Peak area in the White Mountains straddling the California/Nevada border, and from one disjunct Sierra Nevada occurrence in western Mono County, California. Depending on the mapping criteria, Nevada plants comprise either nine smaller occurrences or two larger ones; California has a total of two distinct occurrences. The total number of individuals appears to be around 2,500. This inaccessibility of the species habitat is believed to protect it from many threats, but minor threats include foot and packhorse traffic and feral horses. Climate change is a threat but the impact is not known. The identification of material assumed to be this species should be reviewed for accuracy, as this species is sometimes misidentified.
Range Extent Comments
Boechera pinzliae occurs in the western United States where it occurs in the White Mountains in Esmeralda County, Nevada (Boundary Peak area) and adjacent Mono County, California. Also, there is one disjunct occurrence known from the Sierra Nevada Mountains, California in western Mono County. There are a couple of specimens that need review, and which may be range extensions (J. Morefield, pers. comm., 2021).
Occurrences Comments
In Nevada, there are nine occurrences mapped with a 0.1 mile separation distance, but a separation distance of 0.6 miles (1 km) would aggregate these into just two separate occurrences (Morefield 2001). In California, 2 occurrences have been mapped, 1 near the Nevada occurrences and 1 at a disjunct locality in western Mono County.
Threat Impact Comments
The most significant threat to this species is climate change (J. Morefield, pers. comm., 2021). This species is tolerant of somewhat loose soils (Morefield 2001). No threats are currently known at the California sites; at least one of the two sites is relatively remote with difficult access.
Ecology & Habitat

Diagnostic Characteristics

Easily to identify in the field when in fruit due to its disproportionately large purple pods, which are often as large or larger than the entire plant (Kartesz 1988). Per Rollins (1982), closely related to A. pygmaea and A. platysperma. The one to three erect or ascending siliques of A. pinzliae are narrower than in either of the other species. Its seeds are also smaller, less flattened, and more narrowly winged than either of the other species. Also distinguished by its trichomes, which are dendritically-branched with many branches, fine, and densely packed on the leaf surface; A. pygmaea has coarse, simple or forked trichomes; A. platysperma also has dendritcally-branched trichomes, but they are relatively coarse with just 3-5 branches and are noticeably spaced. Finally, the dense, abundant pubescence of A. pinzliae extends to the upper stems and even sparsely to the pedicels, whereas the upper parts of plants of the other two species are glabrous (Rollins 1982).

Habitat

Subalpine to alpine, occurring on mountain slopes in steep dry drainages, avalanche chutes, talus of cirques, and snow depressions on north to east aspects. Soil is deep, loose, sandy to gravelly, and granitic. Sites tends to have a sparse cover of other species such as Ericameria suffruticosa, Eriophyllum lanatum var. integrifolium, Erysimum capitatum, Arabis platysperma, and Raillardella argentea, Zones of occurrence include subalpine coniferous forest, subalpine sagebrush, and alpine fell-field. 3000-3500 m.

Ecology

This species flowers in July (Flora North America 2010).
Terrestrial Habitats
Forest/WoodlandForest - ConiferAlpineBare rock/talus/scree
Other Nations (1)
United StatesN1
ProvinceRankNative
NevadaS1Yes
CaliforniaS1Yes
Threat Assessments
ThreatScopeSeverityTiming
11 - Climate change & severe weatherPervasive (71-100%)Serious - slightHigh (continuing)

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Plant Characteristics
DurationPERENNIAL, Long-lived
Economic Value (Genus)No
Roadless Areas (1)
Nevada (1)
AreaForestAcres
Boundary Peak (NV)Inyo National Forest21,851
References (11)
  1. California Department of Fish and Game. 2000. Natural Diversity Database (RareFind 2), Version 2.1.2, January 25, 2000. Downloaded in 2003.
  2. California Native Plant Society (CNPS). 2001. Inventory of Rare and Endangered Plants of California (sixth edition). Rare Plant Scientific Advisory Committee, David P. Tibor, Convening Editor. California Native Plant Society. Sacramento, CA. x + 388pp.
  3. Flora of North America Editorial Committee (FNA). 2010. Flora of North America north of Mexico. Vol. 7. Magnoliophyta: Salicaceae to Brassicaceae. Oxford University Press, New York. xxii + 797 pp.
  4. Kartesz, J.T. 1988. A flora of Nevada. Ph.D. dissertation. Univ. of Nevada, Reno. 3 volumes. 1729 pp.
  5. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  6. Lazar, Kristi. Personal communication. Lead Botanist. California Natural Diversity Database, Department of Fish and Wildlife, Sacramento.
  7. Morefield, J.D., editor. 2001. Nevada rare plant atlas [with rare plant fact sheets]. Available as a pdf file at: http://heritage.nv.gov/atlas/atlas.html. Compiled by the Nevada Natural Heritage Program, Carson City, for the U.S. Fish and Wildlife Service, Reno, Nevada.
  8. Morefield, Jim. Personal Communication. Botanist, Nevada Natural Heritage Program, Department of Conservation and Natural Resources, Carson City, Nevada.
  9. Rollins, R. C. 1982. Studies on <i>Arabis </i>(Cruciferae) of western North America II. Contributions from The Grey Herbarium of Harvard University 212:107-111.
  10. Rollins, R.C. 1993a. The Cruciferae of continental North America: Systematics of the mustard family from the Arctic to Panama. Stanford Univ. Press, Stanford, California. 976 pp.
  11. Weixelman, D., and D. Atwood. 1990. Toiyabe National Forest sensitive plants field guide. U.S. Forest Service, Intermountain Region, Ogden, UT. 123 pp.