Arctostaphylos myrtifolia

Arctostaphylos myrtifolia

Critically Imperiled  (NatureServe)
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Ericales
Family: Ericaceae
Genus: Arctostaphylos
Species:
A. myrtifolia
Binomial name
Arctostaphylos myrtifolia

Arctostaphylos myrtifolia is a rare species of manzanita known by the common name Ione manzanita. It is endemic to the Sierra Nevada foothills of California. It grows in the chaparral and woodland plant community on a distinctive acidic soil series, an oxisol of the Eocene-era Ione Formation, in western Amador and northern Calaveras counties.[2] There are only eleven occurrences, of which three have not been recorded since 1976.[3] This is a federally listed threatened species.[1]

Description

Arctostaphylos myrtifolia is a red-barked, bristly shrub reaching just over a meter in maximum height. The small bright green leaves are coated in tiny glandular hairs and are shiny but rough in texture. They are less than 2 centimeters long. The inflorescence is a raceme of urn-shaped manzanita flowers on bright red branches. The fruit is a cylindrical drupe only a few millimeters long.

Conservation

A major threat to this rare endemic plant is a pair of fungal diseases. A branch canker caused by species of Fusicoccum, including F. aesculi, causes some mortality, and root and crown rot caused by Phytophthora cinnamomi has destroyed entire stands of the manzanita and prevented its regrowth in patches of infested soil.[4] These microorganisms, as well as a newly identified one, Phytophthora cambivora, are spreading rapidly and may soon reach the entire range of the plant's distribution. Because of this threat, which may lead to the extinction of the species, the United States Fish and Wildlife Service has recommended that it be upgraded from threatened to endangered status.[5]

See also

References

  1. ^ a b "Ione manzanita (Arctostaphylos myrtifolia)". Environmental Conservation Online System. U.S. Fish & Wildlife Service. Retrieved 20 January 2024.
  2. ^ a b Tarp, Kirsten; Davis, Jason; Sacramento Field Office, U.S. Fish and Wildlife Service (26 May 1999). "Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for the Plant Eriogonum apricum (inclusive of vars. apricum and prostratum) (Ione Buckwheat) and Threatened Status for the Plant Arctostaphylos myrtifolia (Ione Manzanita)". Federal Register. 64 (101): 28403–28413. 64 FR 28403
  3. ^ NatureServe (5 January 2024). "Arctostaphylos myrtifolia". NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer. Arlington, Virginia: NatureServe. Retrieved 20 January 2024.
  4. ^ Swiecki, T. J. and E. A. Bernhardt. Diseases threaten the survival of Ione manzanita (Arctostaphylos myrtifolia). Phytosphere Research March 10, 2003.
  5. ^ USFWS. Eriogonum apricum and Arctostaphylos myrtifolia Five year Review. July 2010.