Field Trip Reports

Botanizing Two Desert Canyons

Grapevine Canyon in Anza Borrego State Park
March 1, 2008

State Park Aide and botanist Larry Hendrickson led two CNPS field trips to study the flora of two desert canyons this March.

On March 1, three 4WD vehicles loaded with a dozen people bounced down Grapevine Canyon, with stops every few hundred yards to look at plants, including with shrubs of the mountain/desert transition zone. As we dropped in elevation, we found more annuals and perennials in bloom, while the riparian species in the colder creek bottom were still in bud. The unusual, large scarlet flower bracts on a Fremont cottonwood were among the visual highlights.

After lunch Larry led us to see rare Borrego bedstraw growing in the boulders in north-facing areas above the creek bed along with several ferns and an uncommon Dudleya. We relocated a population of the rare Cassia covesii, but were startled to find that every individual in this population had died since Larry found it two years ago. Some of us were distracted by the industrious harvester ants hauling their abundant harvest to their ant hills. Like the ants, we were also harvesting: 85 taxa were viewed that day.

Plum Canyon in Anza Borrego State Park
March 21, 2008

Larry led another group to Plum Canyon, named for the abundant Prunus fremontii, called desert plums by the early settlers. We checked out rock outcrops standing above the alluvial slopes, which are little islands of diversity with many species of cacti in bloom. A large patch of the onion relative, Muilla, caught our eye and admiration, and Larry pointed out that "muilla" is "allium" spelled backward.

On the alluvial fan, long-dormant seeds had germinated. We compared several bright little Camissonia growing within a few yards of each other, as well as other belly plants.
We continued up the cool east fork of Plum Canyon, where ferns and other moisture-loving plants were found in shady rock crevices. The canyon walls rear up on each side, with vertical gardens of plants. Wolfberry, a shrubby Solanaceae that was in bloom, is another edible plant found in the canyon. Some old California junipers, unusual to find at this lower elevation, had been hit hard by the several years of drought.

Just as we decided to turn around, we spotted blackbush with beautiful golden flowers, a Rose family shrub that is uncommon in the Colorado Desert. On the return hike we were surprised how much elevation we had gained. We took about an hour to return while we'd spent four hours going up! When we got to the parking area we filled two giant bags with Sahara mustard to help out the beautiful desert that had shown us 104 taxa that day.

Kay Stewart, Larry Hendrickson, and Dave Flietner