Dudleya blochmaniae subsp. brevifolia

Dudleya brevifolia
(Dudleya blochmaniae subsp. brevifolia)
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Core eudicots
Order: Saxifragales
Family: Crassulaceae
Genus: Dudleya
Species: D. blochmaniae
Subspecies: D. b. subsp. brevifolia
Trinomial name
Dudleya blochmaniae subsp. brevifolia
Moran
Synonyms

Dudleya brevifolia
(Moran) Moran [1][2]

Dudleya blochmaniae subsp. brevifolia, now reclassified as Dudleya brevifolia, [1][2] is a rare succulent plant known by the common name short-leaved liveforever or short-leaved dudleya. It was formerly a subspecies of Dudleya blochmaniae. [3]

Distribution

The plant is endemic to coastal sage scrub habitats in southern California, found only in an extremely limited range within southwestern San Diego County. [2] It is found at Torrey Pines State Reserve in the La Jolla neighborhood of the City of San Diego, and several sites in Del Mar, both coastal communities within the county. [4][5]

It is only found on bare surface hardpans of Torrey sandstone with minimal topsoil, from 30–250 metres (98–820 ft) in elevation. [4] Small marble-sized, iron-bearing granules are present at all sites and are likely an edaphic requirement.

Description

Dudleya brevifolia grows into a somewhat erect, small (1–4 cm), cryptic, and corm-like succulent perennial. It has cone-shaped leaves along its hidden stem. It may be brown, reddish-purple, or greenish. [1] It sprouts after significant winter rains (typically December to February).

It bears a branching inflorescence with a few flowers per branch, each opening into a star-shaped bloom with five pointed petals. [1] The bloom period is April to June. [4][2]

The plant produces a many-seeded fruit from a simple pistil, which disperses seeds along a single suture. [1]

Conservation

Their population is highly dependent on rainfall, exploding in population when there is annual rainfall over 10 inches, and drastically shrinking when there is less than 4 inches of annual rainfall. The species is seriously threatened by urbanization, vehicles, foot traffic, and fire break construction. [4]

Total population estimates vary by year and by researcher. [6] Extensive studies have been completed on Carmel Mountain in the Carmel Valley community of San Diego. The Multiple Species Conservation Program (MSCP) of San Diego County estimated the Carmel Mountain population at just 1446 individuals in 2002, and at 113,134 individuals in 2006. [7] Most recently, in 2008, UCLA faculty Dr. Hartmut S. Walter and Matthew Luskin estimated the Carmel Mountain population at over 100,000 individuals. [4][8]

Dudleya brevifolia is a high conservation priority because it exists only in these 5 locations (listed by decreasing average yearly population): Torrey Pines State Reserve, Carmel Mountain (on multiple sites), Crest Canyon, Skeletal Canyon, and Torrey Pines Extension. The total habitat outside of the Torrey Pines State Reserve that contains this species was estimated at just 2,667 square meters.

Endangered species

Dudleya brevifolia is currently listed as an endangered species by the state of California and by the California Native Plant Society. [5][4]

Dudleya blochmaniae subsp. brevifolia was listed as an endangered species by the U.S. Fish and Wildlife Service in January 1982. In October 1996 they withdrew federal protection as an endangered species, citing the threats to the species had diminished and that it was a "covered species" within the Multiple Species Conservation Program (MSCP) of southern San Diego County. [9]

References

  1. 1 2 3 4 5 Jepson eFlora: Dudleya brevifolia . accessed 4 July 2016.
  2. 1 2 3 4 Calflora: Dudleya brevifolia . accessed 4 July 2016.
  3. ↑ Hickman, J. C. (editor) 1993; The Jepson Manual: Higher plants of California (Dudleya blochmaniae subsp. brevifolia treatment); Berkeley, CA. University of California Press.
  4. 1 2 3 4 5 6 California Native Plant Society: Inventory of Rare and Endangered Plants (online edition, v8-02) report on Dudleya brevifolia . accessed 4 July 2016.
  5. 1 2 DFG.ca.gov: Dudleya blochmaniae subsp. brevifolia / Dudleya brevifolia
  6. ↑ USGS.gov: Dudleya blochmaniae subsp. brevifolia
  7. ↑ Sandiego.gov: Dudleya blochmaniae subsp. brevifolia monitoring
  8. ↑ California Native Plant Society, Inventory of Rare and Endangered Plants of California (2001) report of Rare Plant Scientific Advisory Committee, California Native Plant Society. Sacramento, CA. Data tables from electronic copy of the Inventory.
  9. ↑ US-FWS.gov: Dudleya blochmaniae subsp. brevifolia (Endangered species)

External links

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