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Boechera johnstonii

(Munz) Al-Shehbaz

Johnston's Rockcress

G2Imperiled Found in 3 roadless areas NatureServe Explorer →
G2ImperiledGlobal Rank
High - mediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.1236767
Element CodePDBRA40550
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderCapparales
FamilyBrassicaceae
GenusBoechera
Synonyms
Arabis johnstoniiMunz
Concept Reference
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.
Taxonomic Comments
Windham and Al-Shehbaz (2006) find, upon examination of the type specimens of Boechera johnstonii and B. hirshbergiae, that they are too similar to be considered distinct species. The FNA (2010, vol. 7) treatment, the treatment followed here, includes B. hirshbergiae in synonymy of B. johnstonii. In contrast, Kartesz (1994 and 1999) treated them as distinct species.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2022-12-01
Change Date2022-12-01
Edition Date2022-12-01
Edition AuthorsTomaino, A. (2022)
Threat ImpactHigh - medium
Range Extent250-5000 square km (about 100-2000 square miles)
Number of Occurrences6 - 20
Rank Reasons
Boechera johnstonii (in this broader sense including Boechera hirshbergiae) is endemic to southern California in the Cuyamaca Mountains and the San Jacinto Mountains. Threats include grazing, trampling, exotic plants, and development.
Range Extent Comments
Boechera johnstonii (in this broader sense including Boechera hirshbergiae) is known only from the Cuyamaca Mountains and the San Jacinto Mountains, in southern California (Flora of North America Editorial Committee 2010; Baldwin et al. 2012).
Occurrences Comments
There are a total of approximately 13 occurrences (3 in the Cuyamaca Mountains and 10 in the San Jacinto Mountains) (CNDDB 2022).
Threat Impact Comments
Boechera johnstonii is threatened by cattle grazing, trampling, exotic plants, recreational and residential development, and possibly threatened by vegetation/fuels management projects (Narog 2007, CNDDB 2022, CNPS 2022).
Ecology & Habitat

Habitat

Boechera johnstonii is known from rocky areas, gravelly soil, in chaparral, grassland, and open oak/pine woodland (Baldwin et al. 2012).
Terrestrial Habitats
Forest/WoodlandWoodland - MixedShrubland/chaparralGrassland/herbaceous
Other Nations (1)
United StatesN2
ProvinceRankNative
CaliforniaSNRYes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentRestricted (11-30%)Serious - moderate—
2 - Agriculture & aquacultureLarge - restrictedModerate or 11-30% pop. decline—
2.3 - Livestock farming & ranchingLarge - restrictedModerate or 11-30% pop. decline—
7 - Natural system modificationsRestricted (11-30%)Moderate or 11-30% pop. decline—
7.1 - Fire & fire suppressionRestricted (11-30%)Moderate or 11-30% pop. decline—
8 - Invasive & other problematic species, genes & diseasesRestricted (11-30%)Moderate - slight—
8.1 - Invasive non-native/alien species/diseasesRestricted (11-30%)Moderate - slight—

—

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (3)
California (3)
AreaForestAcres
Hixon FlatSan Bernardino National Forest8,095
Pyramid Peak BSan Bernardino National Forest7,194
Rouse HillSan Bernardino National Forest13,745
References (8)
  1. Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken, eds. 2012. The Jepson manual: vascular plants of California. 2nd edition. University of California Press, Berkeley, CA. 1568 pp.
  2. California Native Plant Society (CNPS), Rare Plant Program. 2022. Inventory of Rare and Endangered Plants of California, online edition, v9-01 1.0. Online. Available: https://www.rareplants.cnps.org (accessed 2022).
  3. California Natural Diversity Database (CNDDB). 2022. RareFind Version 5.2.14. California Department of Fish and Game, Sacramento.
  4. 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.
  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. Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.
  7. Narog, M.G., C.J. Sclafani, C. Escobar, K.A. Kramer, J.L. Beyers. 2007. Initial response of <i>Arabis johnstonii </i>Munz to fire. In: Barlow-Irick, P., J. Anderson, C. McDonald, tech eds. Southwestern rare and endangered plants: Proceedings of the Fourth Conference; March 22-26, 2004; Las Cruces, New Mexico. Proceedings. RMRS-P-48CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 83-92.
  8. Windham, M. D. and I. A. Al-Shehbaz. 2006. New and noteworthy species of <i>Boechera</i> (Brassicaceae) I: Sexual diploids. Harvard Papers in Botany 11: 61-88.