The Hunt for the Westernmost Saguaro | KCET
The Hunt for the Westernmost Saguaro
Its gangly silhouette has become synonymous with the entire American West, but the iconic saguaro is actually native to a fairly small area. Despite the label on your Tex-Mex salsa, there are no saguaros in Texas unless they're in botanic gardens or in pots. A stylized saguaro graces the sign of the Cactus Cafe in Wall, South Dakota, but South Dakota is 800 miles from the nearest wild saguaro. Colorado? Nevada? New Mexico? No tienen saguaros.
In fact, the species' range covers about two thirds of the state of Sonora, Mexico, and the southwest third of the state of Arizona, and that is pretty much it excepting one small population in California's Whipple Mountains, in the easternmost part of the state, and an even smaller population in Imperial County. I've come to the Palo Verde Mountains in Imperial County to look for more.
By "an even smaller population" I mean there's one confirmed wild saguaro in Imperial County. Added to that one plant are a lot of rumors that it's not the only one there. That Imperial saguaro is some miles farther west than those in the Whipples, and it's west of Arizona and Sonora as well, which means that it's the World's Westernmost Known Wild Saguaro. According to Rancho Santa Ana Botanic Garden's field botanist Duncan Bell, who has seen it with his own two eyes, that westernmost known saguaro is a healthy, mature tree. It's about 30 feet tall with several robust arms. That would make it about 80 years old, perhaps older.
And then there are the rumors. The BLM's page for the Palo Verde Mountains Wilderness says "Saguaro cactus dot the southeastern part of the wilderness, a rare plant species in California." They provide no citation nor photos. The Calflora database shows that revered botanist Philip Munz found a saguaro in the Cuyamaca-Laguna mountains south of here, just above what is now called Imperial Dam, in the spring of 1931. That individual saguaro is long gone.
CalFlora also has four reports from 1931 of the cactus growing in Tulare County, along the ridgeline of the Sierra Nevada north of Walker Pass, at above 6,000 feet. Whoever made those reports may have been hallucinating from overexertion or dehydration. You're as likely to find saguaros in South Dakota as atop the Sierra, even in the lower elevations around Walker Pass. (That's not a failing in CalFlora: the database contains records from a number of collections of historic observations, some less reliable than others, and no one has the budget to ground-truth every last one.)
A few reported but unconfirmed observations on CalFlora aren't as laughable, though CalFlora describes the "location quality" -- in other words, the likeliness of the report being strictly accurate -- as "Low." One of them seems plausible: along the south edge of the Palo Verde Mountains, just north of Milpitas Wash. It's at the right elevation, and close enough to Arizona that it's easy to imagine a bird landing here a few hours after gorging on saguaro fruit in the Kofa Mountains, and planting a new population.
The Palo Verde Mountains are a small, dark range about twenty miles south of Blythe. Their geology is complex. I'm here as part of a group of a dozen people taking part in a two-day California Native Plant Society Rare Plant Treasure Hunt, with support from the ecological volunteer service group Habitat Work, and we spent yesterday clambering from wash to crumbling small peak, over volcanic tuff, desert pavement, five-million-year-old tufa and siltstone of the Bouse Formation, and sand in washes and deep drifts. Everywhere were agates, jaspers, small geodes and nodules.
Yesterday we explored the eastern edges of the range, wandering up washes and over ridges, looking for a few rare plants other than saguaros. Duncan Bell collected a few specimens of the rare plant Condalia globosa var. pubescens, a tough-looking, small-leaved shrub that grows in washes among ironwoods and palo verdes, and whose range in the Sonoran Desert includes only this small corner of California. Bell's collections will be catalogued in the Rancho Santa Ana Bot Garden's herbarium, providing scientists with yet more data on the biodiversity of this part of the desert. As the day grew hot we found a slot canyon where flash floods had carved a deep cleft in the old Bouse lakebed. Most of us relaxed in the relative cool beneath a giant slab of conglomerated rocks cemented with limestone, a near-cave with a soft gravel floor.
Today is cooler, and we're reasonably well rested after a windy night, so our hiking plans are a bit more ambitious. We're heading for that plausible CalFlora location a mile or so inside the Palo Verde Wilderness, a little under 1.5 miles to the west of the cherrystemmed road where we've parked. That's an "as the crow flies" distance.The Palo Verde Mountains are low, but they're rugged; abrupt ridges incised with deep canyons. A straight-line path between our vehicles and our goal would involve climbing and descending a couple of 300-foot cliffs. Fortunately, the wilderness is laced with alternative routes. Broad washes wind around the cliffs. Slightly sketchy trails made by the local burro population provide sometimes trustworthy routes over the lower passes. One of our number has a handheld GPS with our goal entered as a destination point, and we approximate and reapproximate the best and likeliest route as each turn reveals new obstacles.
Not that our halting, indirect path constitutes a waste of time. For one thing, saguaros could, technically speaking, be growing anywhere along here. There are no majestic specimens in evidence, but I scan the wash banks for juveniles. Saguaros can be pretty old by the time they're noticeable. In Saguaro National Park near Tucson, a decade-old saguaro has typically grown only about two inches tall. By most accounts, saguaros here in the west end of the range grow at about half that rate. To be noticeable at a fair distance, a saguaro here might have to be about 40 years old. The younger ones could easily be missed, small olive-drab barrels with gray spines hiding beneath a sheltering palo verde or ironwood. I look beneath each tree we pass.
There are other plants worth noting here. The hillsides are close to barren. There has been almost no rain here this year. The washes, where that little bit of precip has been funneled, hold some deep-rooted shrubs, a few annuals. We find another Condalia or two. Some stretches of wash hold good numbers of pygmy poppy, Eschscholzia minutiflora, a close relative of the California poppy that differs from its cousin mainly in its much smaller stature. These poppies have flowers about a quarter inch across.
I spot an individual brown-eyed primrose, Camissonia claviformis, almost done blooming. There are lots of the appealingly-named Devil's spineflower, Chorizanthe rigida, an herb with spines so persistent that its late-season dead husks could be mistaken for tiny chollas. There are also actual tiny chollas, and bigger chollas as well. There are forget-me-nots, Cryptantha, little white flowers on fuzzy stems that even the botanists in the crowd won't venture to identify to the species level without a dissecting scope and forceps. There's brittlebush and big galleta grass and desert trumpet, and we roust a couple of fat deer who've been feasting on them. (We later find the freshly chewed stems of a desert trumpet near where the deer had first exploded into flight.)
We see a couple dozen species along our three- or four-mile path, in fact, many of them not previously recorded from this spot. That's not unusual. The desert is largely unexplored by botanists, even though those who do work in the area do a prodigious amount of exploring. There is just simply too much desert to explore, and too few botanists to go around. Pick a remote canyon at random, walk into it more than five miles from the pavement, and it's reasonably likely that even some of the common plants there won't have been formally recorded for that location. The California desert is a botanical frontier, and there are discoveries to be made around every bend of the wash. You can confirm the existence of a species in a place where it's been suspected, but not known for sure, to exist. You can extend the range of a species to a place where no one even thought it might grow. You can find species that are altogether new.
You can also fail to come up with confirmation of vague reports of a species' presence, which is what we seem to be doing with the saguaro. Almost to our GPS coordinate goal, we emerge from a cleft in a deep canyon and walk out onto a broad plain incised with smaller arroyos. We pick our way down into the gullies, power up out of them on the other side, then angle along 30-degree slopes covered with loose gravel, the footing like ball bearings on plywood. We've got a million-dollar view here out across the Milpitas Wash basin to the Chocolate Mountains in the south, and northward toward the volcanic heart of the Palo Verdes. Gaining a bit of altitude as we walk north, we can see hundreds of square miles of desert arrayed around us.
But we can't see any saguaros. No majestic cactus arms reach for the sky. barrel-shaped plants seen in peripheral vision turn out to be unrelated barrel cacti. Unless the plants in this reported location are all either under age 40 or perfectly hidden in washes, which is pretty unlikely, there are no saguaros here.
It's a discovery nonetheless. Negative results are still results. A desert is an ecosystem defined by the absence of things: water, shade, nutrients, vegetation. In the case of this bit of desert, the absent vegetation would seem to include saguaros. We're a bit crestfallen. Even though we've learned something important, it's not so easy to take a triumphant photo of a huge cactus you didn't find (the above photo is from Brenda, Arizona last year). But it's a beautiful day for the hike back to where we parked. Besides, now we've got an excuse to come back and look in other spots. There's plenty of rugged terrain elsewhere in the Palo Verdes where the giant cacti might lurk. Our searching today has only nicked the surface of this little range. The undiscovered westernmost wild saguaro may still be somewhere nearby, clinging to a remote slope just out of range of our binoculars, just one of the thousands of things yet to be learned about the California Deserts.
Chris Clarke is an environmental writer of two decades standing. Author of Walking With Zeke, he writes from Palm Springs regularly at his acclaimed blog Coyote Crossing and comments on desert issues on KCET weekly. Read his recent posts here.
For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.
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