Carson Ridge

To the north of Alpine Lake, this high, rocky ridge runs several kilometers to the northwest and supports a unique vegetative association. Chaparral is the dominant community and includes chamise, Adenostoma fasciculatum, Ceanothus jepsonii, Ceanothus oliganthus var. sorediatus and Pickeringia montana, with some bishop pine, Pinus muricata, interspersed. There is also some coastal prairie and mixed evergreen forest.

Botanically, the area of greatest interest is on the serpentine soils which are marked by serpentine outcrops. Here is found the Sargent cypress, Cupressus sargentii, in a unique "pygmy" form, maturing when only a meter or so high. On Mount Tamalpais, the nearest and only other population in the County, the cypress grows as a tree up to 15 meters (50 feet) high.

Several rare plants are found in the area, including Arctostaphylos virgata, an endemic restricted to Marin County, Hesperolinon congestum, known from Marin and San Mateo Counties, Streptanthus batrachopus, known from only two other stations, both in Marin, and Sidalcea hickmanii ssp. viridis, which is known only from this area.

Two other rare plants are found nearby, Arctostaphylos hookeri ssp. montana and Arabis blepharophylla.

Integrity: Relatively undisturbed; there are various trails as well as a road in the lower section.

Use: Educational, research, observational, on public portion. Remainder, private.

April 1976