Monday, April 5, 2010

Morro manzanita

The Morro manzanita (Arctostaphylos morroensis, Ericaceae family) is a narrowly endemic plant species restricted to a portion of coastal area in San Luis Obispo County, California. It is an erect shrub, which becomes arborescent with old age. It can be distinguished from other species of co-occurring manzanitas by its persistent shreddy bark and densely hairy lower leaf surfaces [1]. The leaves are ovate to elliptic in shape. Morro manzanitas are typically flowering between December and March.
Habitats of Morro manzanitas are sand dune areas and maritime chaparral, which are found south of Morro Bay, for example, in Montaña de Oro State Park and the Elfin Forest Preserve in Los Osos, where they occur along with ancient pygmy coastal live oaks (Quercus agrifolia) and wedgeleaf ceanothus (Ceanothus cuneatus) [2]. A Montaña de Oro State Park interpretative board gives the following information:
Morro manzanita is a unique shrub of limited distribution occurring primarily on ancient sand dunes only in the South Bay region. This coastal species is associated with maritime chaparral, coast live oak, and dune scrub plant communities. It provides an excellent wildlife habitat for resident and migratory species.

Guided walks are offered occasionally through the Elfin Forest nature preserve. The nearby State Park has various trailheads from where you can start a self-guided tour by staying on the marked trails through the sand dunes.

[1] C. Tyler, D. Odion and D. Meade: Ecological Studies of Morro Manzanita (Arctostaphylos morroensis), Seed Ecology, and Reproductive Biology. Marine Sciences Institute, University of California, Santa Barbara, CA 93106, August 1998. PDF.
[2] R. W. Halsey: Chaparral: Pure California. Fremontia Fall 2007, 35 (4), pp. 2-7.
[3] Bureau of Land Management, California: Morro Manzanita (Arctostaphylos morroensis).

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