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Dudleya multicaulis

(Rose) Moran

Many-stem Dudleya

G2Imperiled Found in 3 roadless areas NatureServe Explorer →
G2ImperiledGlobal Rank
Very high - highThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.135243
Element CodePDCRA040H0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderRosales
FamilyCrassulaceae
GenusDudleya
Other Common Names
Many-stemmed Dudleya (EN)
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.
Conservation Status
Review Date2015-07-21
Change Date1984-11-05
Edition Date1991-12-20
Edition AuthorsAnnable, C., rev. D. Gries, rev. K. Gravuer (2009)
Threat ImpactVery high - high
Range Extent1000-5000 square km (about 400-2000 square miles)
Number of Occurrences21 - 80
Rank Reasons
Endemic to the South Coast region of California, in Orange, Los Angeles, Riverside, and San Diego counties (historically also in San Bernardino County). 31-80 occurrences are believed extant; at least 31 - likely many more - occurrences are considered historical or extirpated. This species is continuing to decline. Over half of known occurrences are on private land. Highly threatened by residential development and road construction/maintenance, with numerous occurrences impacted. Lesser threats include grazing, exotic plants, recreational activities, fire reduction management, and mining (clay, sand, gravel).
Range Extent Comments
Endemic to the South Coast bioregion (coastal plain) of southern California (Hickman 1993), in Orange, Los Angeles, Riverside, and San Diego Counties; also a few occurrences documented in San Bernardino County, but all now considered historical (most recent observation = 1983). Patchy distribution associated with the imperiled coastal sage scrub community (Marchant et al. 1998). Using GIS tools, range extent was calculated to be approximately 2500 square km.
Occurrences Comments
Approximately 31 occurrences are believed extant, with a further 49 of unknown status. An additional 25 occurrences are considered historical and at least 6, likely many more, have been extirpated. It has been noted that "population boundaries may be difficult to delineate" for this species. Occurrences might be slightly fewer in number if mapped using a larger separation distance; however, even using a 2 x 2 km grid (as done for Area of Occupancy calculation), greater than 24 distinct grid cells are still occupied by extant occurrences.
Threat Impact Comments
Development (predominantly residential) and road construction/maintenance are the primary threats; large numbers of occurrences are impacted. Grazing, exotic plants, and impacts from recreational activities also threaten a significant number of occurrences. Land management activities associated with fire reduction (e.g. disking to reduce fuel) and mining (clay, sand, gravel) each threaten a few occurrences. Military maneuvers may threaten a few occurrences in San Diego County (Reiser 1994). Overall, this species is considered seriously threatened (CNPS 2009).
Ecology & Habitat

Diagnostic Characteristics

Dudelya multicaulis can be characterized by its rosette leaves linear-lanceolate, not narrowed at base, 4-15 cm long; petals connate for 1-2 mm; flowers yellow, odorless (Munz, 1959).

Habitat

Often associated with heavy clay soils in barrens, dry stony places, or thinly vegetated openings, within coastal sage scrub, chaparral, and valley and foothill grassland (e.g. southern needlegrass grassland) communities. Associated species include coast turkish rugging (Chorizanthe staticoides ssp. chrysacantha), Palmer's grappling hook (Harpagonella palmeri), Munz's onion (Allium munzii), chocolate lily (Fritillaria biflora), manicure lupine (Lupinus bicolor), purple needlegrass (Nasella pulchra), foothill needlegrass (Nasella lepida), California buckwheat (Eriogonum fasciculatum), California sagebrush (Artemisia californica), and California juniper (Juniperus californica). 0 - 800 m.

Reproduction

Seeds are dispersed by wind and water.
Terrestrial Habitats
Shrubland/chaparralGrassland/herbaceousBarrens
Other Nations (1)
United StatesN2
ProvinceRankNative
CaliforniaS2Yes
Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (3)
California (3)
AreaForestAcres
ColdwaterCleveland National Forest8,402
Cucamonga CSan Bernardino National Forest4,106
LaddCleveland National Forest5,300
References (7)
  1. California Native Plant Society (CNPS). 2009. Inventory of Rare and Endangered Plants. California Native Plant Society. Sacramento, CA. Online. Available: http://www.cnps.org/inventory (accessed 2009).
  2. Flora of North America Editorial Committee (FNA). 2009. Flora of North America north of Mexico. Vol. 8. Magnoliophyta: Paeoniaceae to Ericaceae. Oxford University Press, New York. xxiv + 585 pp.
  3. Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 pp.
  4. 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.
  5. Marchant, T. A., R. Alarcon, J. A. Simonsen, and H. Koopowitz. 1998. Population ecology of <i>Dudleya multicaulis</i> (Crassulaceae): A rare narrow endemic. Madroño 45(3): 215-220.
  6. Munz, P.A., with D.D. Keck. 1959. A California flora. Univ. California Press, Berkeley. 1681 pp.
  7. Reiser, C. 1994. Rare plants of San Diego County. http://sandiego.sierraclub.org/rareplants/. Site updated October 6, 2001 by E. Kanner and B. Buffett. Site accessed 2003.