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IN THE FIELD: Corte Madera Mountain

By Tom Oberbauer

Back in January of 1978, I hiked up onto Corte Madera Mountain with a friend, Tom Scott (now with UC Berkeley and UC Riverside), who had been studying Golden Eagles in San Diego County. Bald Eagles were wintering at Corte Madera Lake. After postponing the hike due to rain, that was a good rain season, we drove out to Corte Madera Lake, which was accessible because Tom Scott had a key, and we hiked up the north side of Corte Madera Mountain on a little used trail. The trail climbed through a woodland of mostly coast live oak (Quercus agrifolia), but also Coulter pine (Pinus coulteri), as well as Jeffrey pine (Pinus jeffreyi). It was foggy going up and the view was obscured.

IN THE FIELD: Corte Madera Mountain
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In The Field: The New Santa Fe Valley Trail

By Jürgen Schrenk

Recently, the new Santa Fe Valley Trail, connecting the San Dieguito River Park’s Del Dios Gorge Trail with the Lusardi Creek Preserve, was opened to the public. The beginning of the trail took us through fields of Menzies’ Goldenbush (Isocoma menziesii var. menziesii).

In The Field: The New Santa Fe Valley Trail
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The Desert a Month after Monsoonal Rains

By Jürgen Schrenk

After yet another week of waiting for the temps to go down watching our Monarch production and limiting our walks to local parks, I was worried that I might completely miss the monsoonal “spring” in the desert. So, I went on a quick drive along S-2

The Desert a Month after Monsoonal Rains
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CNPS-SD Helps With Rare Plant Surveys

By Justin Daniel, Vice President, Rare Plants Co-chair

With vaccinations allowing more contact outdoors and a workload a year behind, it's been a busy time a few of us to help some of our fantastic environmental conservancy organizations around San Diego County by assisting them in their rare plant surveys. The following are glimpses into some of the recent surveys. Come along for the ride and reach out to support our partners, too!

CNPS-SD Helps With Rare Plant Surveys
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The Mount Laguna Surprise

By Tom Oberbauer

…The next week, I drove up and hiked to the location I visited in December and sure enough, the display of Platystemon californica (above) was pretty amazing. Sheets of color extended across the slopes leading into the center of the meadow. I spent some time attempting to photograph and create video of the breeze gently shaking the small flowers. From this location, the view of the meadow ranges across its full length, extending more than three miles in the distance to the south. Laguna Lake also contained a good level of water reflecting the blue sky, apparently left over from the previous two good rainfall seasons. I attempted to capture the view of the flowers with the lake and end of the meadow in the distance. The breeze and the movement of the flowers in this manner always reminds me of when I was a child and my family visited Estes Park in Colorado and we observed alpine wildflowers…

The Mount Laguna Surprise

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El Cajon Mountain

By Tom Oberbauer, Past President CNPS-San Diego

As one drives east on Interstate 8, between El Cajon and Alpine, a large mountain is to the north. It is notable for the high ridge point that has nearly shear cliffs on two pointed sides. The light-colored granodiorite cliffs are visible from far away. If one drives up the San Diego River in Lakeside traveling to El Monte Park, the mass of the mountain becomes even more visible, dropping directly into the Valley. The true name of this mountain is El Cajon Mountain because of its proximity to El Cajon and El Cajon Valley. El Cajon istranslated to be “the box”. It seems a bit amusing that a mountain would be named box mountain. However, everyone who sees the mountains and those who live near it refer to it as El Capitan. El Capitan or “the captain” is the name of one of the famous landmarks in Yosemite, and its resemblance to that landmark is the reason that this mountain is usually referred to as El Capitan. In fact, El Capitan High School and El Capitan Dam both reflect that local name for the fountains.

The mountain is not really large, being 3,651 feet in elevation, but it is located in the midst of granitic rock domes – massive plutons of rock that are the product of subduction and fractionization of molten material. During the Cretaceous, 145 to 66 million years ago, the sea floor was subducted beneath the north American plate. As the sea floor plate was forced downward beneath the continental crustal mass, it was heated and became molten. The heavier basaltic material stayed low in the molten column but lighter materials, such as quartz and feldspar, bowed upward due to its lighter mass being distilled out of the mix of molten rock, far below the earth’s surface. The lighter molten rock formed large balloon shaped blobs that intruded upward, heating their surroundings but also cooling very slowly, maybe taking millions of years. The slow cooling process allowed for crystals and chunks of orthoclase and plagioclase feldspar within the quartz to grow. Impurities of iron and other minerals also grow into crystals, producing their light gray white or slightly tan rock with flecks of black mica and black tourmaline or shorl.

These large solid balloon-shaped blobs of slowly cooled rock (plutons) stayed beneath the surface until plate tectonic forces raised the crust upward. As the erosive forces of millions of years of rain and weathering occurred, the overlaying surfaces eroded away, the large plutons of hard granitic material were exposed to the surface and even thrust higher upward. Famous plutons include Half Dome and El Capitan in Yosemite.