Clarkia franciscana (Flowering Plants)

Species Description

The Presidio clarkia is a member of the evening primrose family. It is a small annual herbaceous plant. The clarkia grows to 16 inches tall, with leaves which are very small and narrow, few in number, and beautiful lavender-pink petals, lighter in color toward the middle of the flower and with a reddish-purple basal spot; plants flower from May to July.

The population size fluctuates from year to year, and was particularly low before being protected under the Endangered Species Act in 1995. Urban development and invasive species are both considered threats to the remaining plants.

The Presidio Clarkia is found only in two locations in the Presidio and three locations in the Oakland Hills. Its range is limited to grassland and coastal scrub. Like the Raven’s Manzanita, it grows in serpentine soils from weathered volcanic rocks. Also like the Raven’s Manzanita, it was first identified by Peter Raven, the eminent botanist and San Francisco native.

The populations in the Oakland hills lie within 0.5 miles of each other; the largest within Redwood Regional Park; the other populations, one near the Oakland Hills Tennis Club and the other near Crestmont Drive, are both threatened by development plans. A contested development project on Crestmont Drive was finally approved in June, 2007; environmentalists continue to monitor the Crestmont Drive development to protect the clarkia. The species was protected by the Endangered Species Act in 1995.

The Clarkia growing in the Presidio have benefited from conservation measures, focused on the grassland at Inspiration Point, including the installation of fencing and removal of adjacent Monterey pines; these efforts have increased both the total numbers and total area inhabited by the Clarkia. During the summer of 2007, the Presidio Trust and National Park Service are testing new methods to control non-native plants, including small controlled fires, which will be set within a tall, portable metal box, to connect fragmented grassland areas.

Conservation Action Item

Aid Clarkia recovery:
Help monitor and restore Clarkia in Tennessee Hollow

Inspiration Point is home to the Presidio Clarkia, where it is currently threatened by exotic plant species. Since 1994, the number of Presidio clarkia individuals has been monitored annually. Clarkia has risen tenfold at Inspiration point from a low of 4000 in 1998 to over 40,000, likely due to site stewardship and favorable rains. Help with habitat restoration efforts for the Presidio Clarkia in the Golden Gate National Parks.

Big Year Competitors have reported 5 sightings and taken 4 actions to help this species recover so far this year.

Trips

• CANCELED-Presidio Clarkia and Marin Dwarf-Flax Habitat Restoration
  Saturday, 05 Jun 2010, 09:00 - 12:00 Pacific Time (US & Canada)
• Presidio Clarkia Monitoring
  Thursday, 20 May 2010, 09:00 - 12:00 Pacific Time (US & Canada)