Field Trips Log
April 2007

Thursday-Sunday, 5-8 April 2007 (San Diego and Imperial Counties)

I didn't hold out much hope for any great floristic displays when I set out southward to meet a group from the Jepson Herbarium for our San Diego and Imperial Counties field trip, and as it turned out my expectations were accurate. Our trip leader, Dr. Jon Rebman of the San Diego County Natural History Museum, a person as or more knowledgeable about San Diego flora than anyone, described it as the worst year he'd ever seen. Nonethe-
less I had hopes that he might know of some moist pockets where we could see at least some things I hadn't seen before, and this also turned out to be true. We met on Thursday night at the Bow Willow Campground in the Bow Willow Canyon area of southern Anza Borrego Desert State Park which is off the S-2 about 15 miles north of Ocotillo and not far from the Carrizo Badlands. I had decided to stay at a motel in El Centro, about a 45-minute drive away.

That evening over dinner, Jon described the dry conditions prevalent all over the area and informed us that the field trip itinerary was being planned anew accordingly. One of the areas that I really wanted to get into was the Algodones Dunes of Imperial County, which I had only visited once before in the spring of 2004, but Jon informed us that that area was a complete bust and there was no point in going over there. Instead, tomorrow we would drive westward toward San Diego and check out some locations along Mountain Springs Grade in the In-Ko-Pah
Mountains, where I knew we would find at least one species I hadn't encountered before, the Wolf's cholla, and then drive along the Imperial Highway and stop at a number of localities. On Saturday we would go even further westward over the southern shoulders of the Laguna Mountains to the Descanso area south of Cuyamaca. Sunday was up in the air.

Friday morning we packed our lunches and headed off in a 12-passenger van to the In-Ko-Pahs, a mountain range named for the Indians who once inhabited this region. This is a transitional area between higher-elevation chaparral shrublands and low Colorado Desert scrub including ocotillos, agaves, chollas and catclaws, and indeed it did seem very dry. We could see a small palm oasis in the distance, but we were surrounded by rocky terrain which nevertheless supported desert agaves (Agave deserti) sending up stalks perhaps shorter than usual and clumps of beargrass (Nolina bigelovii). Mojave yuccas (Yucca schidigera), barrel cactuses (Ferocactus cylindraceus) and ocotillos both in leaf and in bloom were also dotted across the landscape, along with a few California junipers. But we were there to see the Wolf's cholla (Cylindropuntia wolfii), a very erect branching cholla with dense pale-brownish spines, and a species that as we were to discover although rare in California is "locally common." And there were many of them, this apparently being one place other than Baja where they do exist in great numbers. In fact, it is the dominant cholla there. Barrel cactus both short and tall popped up all over the place, including a couple with blooms, but it was the fishhook or nipple cactus (Mammillaria dioica) that I was interested in since I had never seen it in bloom before. We kept seeing the cute little cactuses hiding amongst the rocks and finally we found a few that had beautiful flowers almost as big as the cactuses themselves. We also encountered some Arizona chalk dudleyas (Dudleya arizonica), formerly a subspecies of Dudleya pulverulenta but a taxon being assigned full species status in the next edition of the Jepson Manual.

At our next couple of stops back along the S-2 (Imperial Highway), Jon had promised us some species with blooms, and although that was true, you had to look hard to find the few blooms that were in evidence, and many of the species Jon showed us were not in fact in flower. Although I had seen most all of these species, many of the trip participants from Northern California were unfamiliar with them. We saw a single turtleback (Psathyrotes ramosissima), a sandpaper plant (Petalonyx thurberi), some Emory indigo bushes (Psorothamnus emoryi) including a few hosting the fascinating little parasitic species Thurber's stemsucker (Pilostyles thurberi), a climbing milkweed (Sarcostemma cynanchoides) in good flower, some Bebbia and a couple of different Cheilanthes species, viscida and covillei. A new taxon for many of us was the cane or snake cholla (Cylindropuntia californica var. parkeri), a subspecies of what used to be called Opuntia parryi. The genus Opuntia is now in the process of being separated into three genera, Cylindropuntia for the "true"cylindrical-stemmed chollas, Opuntia for the flat-padded chollas, and Grusonia. We also saw a good many Fosberg's cholla (Opuntia X fosbergii, also referred to as Hoffman's cholla or pink teddybear cholla), which is considered a natural hybrid of Opuntia bigelovii and possibly O. echinocarpa, and which according to Reiser's Rare Plants of San Diego has a "very limited range from Mason Valley south to Canebrake Canyon; primarily west of Highway S-2." One species that we did see with some lovely flowers on it was white rhatany (Krameria grayi).

Later we saw some desert prickly pear (Opuntia phaecantha) and teddybear cactus (Opuntia bigelovii), and some Engelmann's hedgehog cactus (Echinocereus engelmannii). It had been a fairly warm day, but when we returned to the campground, after a refreshing cold beer, we all trooped out into the area nearby to inspect the Gander's cholla (Opuntia ganderi) that was fairly common there.

After breakfast on Saturday, we loaded up and headed east again on Interstate 8 toward San Diego, exiting at the Japatul Valley exit for Rt. 79. We headed to an area called Horsethief Canyon which indeed did appear to be greener than any areas further to the east. We started walking down a fire road then turned off onto a trail that wound fairly steeply downhill. Things we saw in bloom (although again blooms were sparse) were ropevine (Clematis pauciflora), green miner's lettuce (Claytonia parviflora ssp. viridis), slender-pod jewelflower (Caulanthus heterophyllus var. heterophyllus), two-tone everlasting (Gnaphalium bicolor), and wild peony (Paeonia californica). We looked for and further down found some specimens of a fern that Jon is in the process of publishing as a new taxon, Pentagramma triangularis var. nov., a fern with extremely farinose fronds. Down along the creek, I was able to photograph a couple of diminutive species that were new to me, spring draba (Draba verna), and dwarf athysanus (Athysanus pusillus), both in bloom.

On Sunday we opted to drive north on the S-2 to an area where we could hike in to a palm oasis. There we saw some interesting things such as alkali goldenbush (Isocoma acradenia var. eremophila), rush seepweed (Suaeda moquinii), more white rhatany, desert thorn (Lycium brevipes), Parry's lipfern (Cheilanthes parryi) and for me the best, white-stemmed milkweed (Asclepias albicans). We followed a small canyon to a couple of clusters of California fan palms (Washingtonia filifera) which unfortunately had had their palm frond skirts burned off, then most people having a long way to go decided it was time to head for home. I was interested in seeing a species that I had only seen before at Rancho Santa Ana Botanic Garden, so Jon and I drove down to the Crucifixion Thorn Natural Area south of Ocotillo, where I was able to investigate a large area with many very large individuals of this uncommon species (Castela emoryi). It is a summer bloomer so I didn't expect to see any flowers but it was nice to finally see this species in a natural area.