Roadless Areas
Home/Species/ Tujunga Bushmallow

Malacothamnus davidsonii

(B.L. Robins.) Greene

Tujunga Bushmallow

G2Imperiled Found in 1 roadless area NatureServe Explorer →
G2ImperiledGlobal Rank
HighThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.1311199
Element CodePDMAL0Q0V0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderMalvales
FamilyMalvaceae
GenusMalacothamnus
Concept Reference
Morse, K. 2023. Malacothamnus: A revised treatment of the genus Malacothamnus (Malvaceae) based on morphological and phylogenetic evidence. Volumes 1-3. Published August 2023, open access book, distributed under the terms of the Creative Commons Attribution License. [https://doi.org/10.6084/m9.figshare.23937051.v1]
Taxonomic Comments
This record represents the narrow concept of Malacothamnus davidsonii not including M. discombobulatus following Morse (2023). The distinct geographic ranges of M. davidsonii and M. discombobulatus are most easily used to separate them (Morse 2023).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-10-07
Change Date2025-10-07
Edition Date2025-10-07
Edition AuthorsTomaino, A. (2025)
Threat ImpactHigh
Range Extent250-1000 square km (about 100-400 square miles)
Number of Occurrences21 - 80
Rank Reasons
Endemic to California, Malacothamnus davidsonii occurs only in Los Angeles county. Numerous threats have been documented for this species including development, recreation, road/trail construction/maintenance, improper burning regime, and non-native plants.
Range Extent Comments
Malacothamnus davidsonii is known only from Los Angeles County, California (Morse 2023). Plants from Monterey and San Luis Obispo counties, California formerly classified as Malacothamnus davidsonii were described as Malacothamnus discombobulatus in 2023 (Morse 2023).
Occurrences Comments
There are at least 40 estimated occurrences over the past 20 years (CNPS 2025).
Threat Impact Comments
Malacothamnus davidsonii is threatened by development, erosion/runoff, foot traffic/trampling, herbicides, improper burning regime, non-native plant impacts, ORV activity, road/trail construction/maintenance, vandalism/dumping/litter, waterway bank protection/maintenance, wood cutting or brush clearing (CNPS 2025).
Ecology & Habitat

Habitat

Malacothamnus davidsonii occurs within Chaparral, Cismontane woodland, Coastal scrub, and Riparian woodland, growing at elevations from 185 to 1140 meters (CNPS 2025).
Terrestrial Habitats
Forest/WoodlandWoodland - HardwoodWoodland - MixedShrubland/chaparral
Palustrine Habitats
FORESTED WETLANDRiparian
Other Nations (1)
United StatesN2
ProvinceRankNative
CaliforniaS2Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentRestricted (11-30%)Serious or 31-70% pop. declineHigh (continuing)
5 - Biological resource useRestricted (11-30%)Serious or 31-70% pop. declineHigh (continuing)
5.3 - Logging & wood harvestingRestricted (11-30%)Serious or 31-70% pop. declineHigh (continuing)
6 - Human intrusions & disturbanceRestricted (11-30%)Serious - moderateHigh (continuing)
6.1 - Recreational activitiesRestricted (11-30%)Serious - moderateHigh (continuing)
7 - Natural system modificationsSmall (1-10%)UnknownUnknown
7.1 - Fire & fire suppressionSmall (1-10%)UnknownUnknown
7.2 - Dams & water management/useSmall (1-10%)UnknownUnknown
8 - Invasive & other problematic species, genes & diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8.1.1 - Unspecified speciesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
9 - PollutionSmall (1-10%)UnknownUnknown
9.4 - Garbage & solid wasteSmall (1-10%)UnknownUnknown

—

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (1)
California (1)
AreaForestAcres
Magic MountainAngeles National Forest15,542
References (8)
  1. CalFlora. 2005. Information on California plants for education, research and conservation. Berkeley, California: The CalFlora Database [web application]. Available: http://www.calflora.org/. (Accessed 2005)
  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. California Native Plant Society (CNPS), Rare Plant Program. 2025. Inventory of Rare and Endangered Plants of California, online edition, v9.5. Online. Available: https://www.rareplants.cnps.org (accessed 2025).
  4. Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 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. Morse, K. 2023. <i>Malacothamnus</i>: A revised treatment of the genus <i>Malacothamnus </i>(Malvaceae) based on morphological and phylogenetic evidence. Volumes 1-3. Published August 2023, open access book, distributed under the terms of the Creative Commons Attribution License. [https://doi.org/10.6084/m9.figshare.23937051.v1]
  7. Morse, K. 2023. <i>Malacothamnus</i>, in Jepson Flora Project (eds.) Jepson eFlora, Revision 12. Online. Available: https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=9579 (accessed 2024).
  8. Munz, P.A., with D.D. Keck. 1959. A California flora. Univ. California Press, Berkeley. 1681 pp.