by Peter Lapshin
|CULTIVAR / КУЛЬТИВАР|
e-Magazine about exotic forms of Cactaceae
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Mojave Desert Cacti
by Vladimir Malov, California USA
Zion National Park
Cylindropuntia echinocarpa, Opuntia polyacantha, Opuntia macrorhisa, Opuntia chlorotica,Opuntia sp 'basilaris', Echinocrerus engelmannii, Echinocereus coccineus
The Zion Canyon entrance of Zion National Park is about 150 miles and a two and half hour drive from Las Vegas. I drove out in the evening, snapped some pictures of the sheer sandstone walls that are the Park's main attraction the coming morning, and then headed away, since my goals here were different from those of the other Park visitors.
Right at the Park entrance and next to the campground where I spent the night I walk up the south-facing slope. To my surprise I see no cacti, but I as I walk all the way to a rock band topping the slope I see Opuntia chlorotica growing like small trees under the cliffs. The plants have large pads the size of two human palms and colored a light bluish-green, adorned with long bright-yellow spines and yellow glochid bunches. From up here I also notice some other Opuntias growing down low and head back down, carefully watching for any Enchninocereus that might be beneath my feet. Sadly, I find the first one with a toe sticking out of my sandals.
Down the slope in the low grass there are Opuntia macrorhisa, Echinocereus engelmanii and some other kind of Opunita that have trouble identifying. The plant is similar to Opintia basilaris, bluish pads with very short glohids, but the pads are larger and longer, with several long macrorhisa-type spines at the pad tip. The fruit is dry and also much like that of the Opintia basilaris, making me think that this is another basilaris variation of some sort of hybrid.
The soil here is wet after recent rain, sandy and brown like the local sandstone rocks.
Next to the road I run into a trail that leads to a sign. One of the rocks nearby, an erect sandstone slab, is covered with Indian petroglyphs. The sign kindly asks the visitors to refrain from adding any others.
Leaving the Park I head out to search for Echinocereus coccineus. A few miles away is a spot where I had seen them during my first visit here six years ago.
Driving past Rockville and Springdale I see a sign telling me to "Imagine living here" as well as a new side road winding uphill. Since it's a south-facing slope I decide to check it out.
Up here there are a little flat area and driveways for the planned houses. Several buildings are already in place, but don't seem occupied, and some work is ongoing for another house. The views are overwhelming – cliffs surrounding the valley and the Zion Canyon. And I even find one Echinocereus coccineus here, growing next to a large flat boulder.
Back on the highway I soon find some familiar landmarks from my old trip here. There's the side valley with a creek cutting into the slope. I park and head in. As I later find out the creek separates a basalt-topped plateau on the left from the other plateau cowered with petrified forest on the fight. Apparently one eruption both created the plateau surrounding the old volcano that rises about ten miles north and also buried an ancient forest with ashes, petrifying it.
First I scan the right slope of the valley. The loose slope is very steep and I have to locate a gully cut into the side in order to clamber up. Here in the gully I find several Echinocereus coccineus plants along with some Opuntia polyacantha. Echinocereus coccineus plants show two different forms, some having stout black spines, while other have thinner, straw-colored ones with black tips.
Higher up the slope flattens out and there are no more Echinocerei, though I do find small Cylindropuntia echinocarpa plants growing along with wide spaced desert shrubs. So I decide to cross the valley and check out the other slope with its dark basalt rocks.
The valley bottom is covered with thin washed sand. The aspens are in full golden fall foliage and grow along with several Yuccas around the small stream that I cross by hopping from rock to rock.
Climbing up the slope I immediately spot a couple of large mounds of Ehinocereus coccineus. Higher up the slope leads me to a ridge with a broad meadow below it. The breezy ridge is a promising place to look for cacti and I follow it up to the basalt rocks band. Along the ridge among the thin low grass I run across Echinocereus coccineus and Echinocereus engelmanii plants. Further up I see some Opuntias. I think this might be the Opuntia engelmannii form, though it's hard for me to tell – they look somewhat like macrorhisas, but have thicker pads and more glochids.
Moving from cactus to cactus I finally reach the base of a small basalt cliff. While thinking about how to climb it, I find the remnants of an old road and cross the cliff. Once more the slope above flattens out, and I can't find any more cacti, so I turn back. From above I saw a larger Echinoereus mound, a bit off my tracks, and decide go to check it out. The plant has well over a hundred heads growing among thick low grass that makes a sort of a meadow on the slope. I can't see any more cacti in the meadow, but one Cylindropuntia bush does stick out.
I'm not sure whether the grasses are local or invasive. Alien grasses are actually a very significant threat to the ecosystems of Arizona. They grow taller and thicker than desert plants, and while this makes for a pretty sight in spring, for nine months out of the year the grass is yellow, dry, and ready to burn. No desert plants, including cacti, can survive the heat of these grass fires. An ecosystem that depends on the ten-year rainy El Nino cycle for new plant germination and that has plants that need another ten years to reach flowering size can be threatened even by occasional fires. Even during the rainy seasons the grasses are dangerous since they compete for water with the native plants, often suppressing them. After ten to fifteen years of vigorous growth the alien plants exhaust the thin desert soils and wither away, leaving the landscape even more naked than before their invasion.
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