Category Archives: nature|botany

Pine Drops

Pine drops (Pterospora andromedea) on the Pacific Crest Trail near Little Jimmy Trail Camp

Pine drops (Pterospora andromedea) and snow plant (Sarcodes sanguinea) are related nonphotosynthetic plants that are found under pine and related trees, primarily in the mountains of the western U.S.

At one time it was believed that these plants were saprophytes, and obtained needed nutrients directly from decaying organic matter in soil. However, research has revealed a more complex parasitic relationship in which the plant obtains carbohydrate from a pine tree, by way of a shared mycorrhizal fungus.

The photograph was taken on the run described in Heat Wave, on July 16, 2006.

Related post: Snow Plant

Lasky Mesa Prickly Pear

Prickly pear on Lasky Mesa in Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch).

This prickly pear on Lasky Mesa appears to have many of the characteristics of the Engelmann prickly-pear, Opuntia engelmannii, but is more likely a cross involving O. engelmannii. One such cross is O. littoralis X (O. engelmannii X O. phaeacantha ) which is referred to as O. ×occidentalis in the Jepson Manual. Here’s a closer view of the stamens and pistil.

From a run in in Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch) on May 23, 2007.

Ahmanson Blue Oak

Photograph of leaves of blue oak in East Las Virgenes Canyon.

Update April 14, 2023. The Ahmanson Blue Oak has died. Please see the post Ahmanson Blue Oak Succumbs to Climate Change.

Blue oak (Quercus douglasii) is a characteristic oak of the lower elevations of the Sierra foothills and coastal mountains, its range essentially encircling California’s Central Valley.

Based on its reported range, Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch) contains one of the southernmost populations of blue oak within its range. However, the predominate deciduous oak in the area is valley oak (Quercus lobata), and occurrences of blue oak appear to be rare. Regional climate modeling suggests that over the next century the range of blue oak could shift northward and diminish to nearly 60% of its current range.

Blue oak is reported to hybridize with valley oak, however a 2005 study suggests hybrids of these species may be more rare than generally accepted.

The photograph of the leaves of a blue oak was taken on a run along East Las Virgenes Canyon to Lasky Mesa on April 24, 2007. A valley oak immediately adjacent to this blue oak was killed in the 2005 Topanga Fire.

Related posts: Ahmanson Blue Oak Succumbs to Climate Change, Valley Oak Savanna, Laskey Mesa Oak

Technical papers:

Modeled regional climate change and California endemic oak ranges.
Kueppers, L.M., M.A. Snyder, L.C. Sloan, E.S. Zavaleta, and Brian Fulfrost. 2005.
Proceedings of the National Academy of Sciences of the United States of America, 102(45): 16281 – 16286.

Limited hybridization between Quercus lobata and Quercus douglasii (Fagaceae) in a mixed stand in central coastal California.
Kathleen J. Craft, Mary V. Ashley and Walter D. Koenig.
American Journal of Botany. 2002;89:1792-1798.

Chaparral Freeze

Freeze damaged Laurel Sumac in Malibu Creek State Park.

Updated March 6, 2007

As evidenced by their survival, native plants are generally well adapted to the environment in which they live. Fire, flood, drought, heat or cold, they’ve seen it all – or nearly so.

On January 14, 2007 many new record low temperatures for the date were set in the Southern California area. Several locations in the San Fernando Valley recorded temperatures in the 20’s. Pierce College in Woodland Hills plunged to a record low of 20°F (-6.7°C).

The freezing temperatures resulted in extensive damage to fruit crops, nursery stock, and landscaping. The brown leaves of freeze damaged shrubs, trees and other plants are a common sight in the Los Angeles suburbs.

Since the freeze, I’ve run in several areas of the Santa Monica Mountains, Santa Susana Mountains and Simi Hills, and most native chaparral shrubs appeared to have weathered the cold temperatures well, exhibiting very minor, if any, visible damage. However, there are some exceptions.

One obvious exception is laurel sumac (Malosma laurina). I first noticed instances of laurel sumac with damaged leaves and stems on a run at Sage Ranch on January 24. Initially, I thought the damage might be limited to sprouting laurel sumac in the 2005 Topanga Fire burn area, but on subsequent runs damaged plants were seen in several areas unaffected by the fire, including Topanga and Malibu Creek State Parks. Now that the dead leaves and stems have turned brown, the affected plants stand out in the chaparral, and the extent of the damage is easy to see.

The sensitivity of Laurel Sumac and other chaparral plants to freezing temperatures and drought has been studied extensively by Dr. Stephen Davis of Pepperdine University’s Seaver College Biology Department. This research confirms that the leaves and stems of laurel sumac are not as tolerent of freezing temperatures as some other chaparral shrubs. This reduced tolerance probably affects the distribution of the plant, favoring its growth in warmer coastal locations and inland microclimates.

Dr. Davis reports that, in addition to laurel sumac, other species that have been damaged at the lower, colder distributions in the Santa Monica Mountains include green bark ceanothus (Ceanothus spinosis), big pod ceanothus (Ceanothus megacarpus), sugar bush (Rhus ovata), and some hairy-leaf ceanothus (Ceanothus oliganthus). The lowest temperature recorded at his field sites was 10.4°F (-12°C).

A factor in the damage is that the freeze occurred during a period of relative drought. As of January 14, Downtown Los Angeles (USC) had recorded only 1.31 inches of rain since (but not including) May 22, 2006 – a period of nearly 8 months.

Although some of laurel sumac’s adaptations to fire and drought may adversely affect the resistance of its foliage to freezing temperatures, it is precisely these adaptations that will enable most of the freeze damaged laurel sumacs to resprout and survive.

The photograph of freeze damaged Laurel Sumac was taken on the Backbone, Bulldog & Beyond run.

Twiggy Wreath Plant?

An ant forages among the florets of a wreath plant at Sage Ranch Park.

An ant forages among the florets of a wreath plant.

I’ve run past wreath plants thousands of times in the chaparral of local open space areas. At a glance, the nondescript wiry brown plant isn’t very appealing. But it’s one of a few plants you’ll see blooming in the chaparral in the Fall, so on a run this last November I took a closer look. This revealed a lavender-tinged composite flower that is anything but mundane. And, as I was to discover, a case of probable mistaken identity, and an example of one of the ways new species occur.

Three field guides in my library identify the plant pictured above as Twiggy Wreath Plant (Stephanomeria virgata). But, as discussed by Tom Chester, there is some confusion regarding it’s characteristics and identity. It could be the case that many Southern California plants previously identified as S. virgata may actually be San Diego Wreath Plant (S. diegensis), including those in the Santa Monica Mountains.

The plants are very similar, but according to the identification key for the genus Stephanomeria in the Jepson Manual can be distinguished by a groove along the length of a seed (achene). This isn’t something easily done in the field. The achenes are so tiny that they are best seen in a strong loupe or a low power microscope. Wayne’s World Volume 9 (Number 3) Fall 2000 has some photographs of the achenes and groove.

So why are S. virgata and S. diegensis so similar? The genetic relationship of various members of the genus Stephanomeria has been researched and it appears likely that S. diegensis is a relatively recent species that resulted from a natural cross of S. exigua and S. virgata.

The photograph of the foraging ant was taken on a run at Sage Ranch on November 5, 2006. Based on examination of some achenes from wreath plants in the area, the plant is probably Stephanomeria diegensis.

Technical papers:

Genetic Evidence for the Hybrid Origin of the Diploid Plant Stephanomeria diegensis

G. P. Gallez, L. D. Gottlieb
Evolution, Vol. 36, No. 6 (Nov., 1982), pp. 1158-1167

Phylogeny of Stephanomeria and related genera (compositae–lactuceae) based on analysis of 18S–26S nuclear rDNA ITS and ETS sequences

Joongku Lee, Bruce G. Baldwin and L. D. Gottlieb
American Journal of Botany. 2002;89:160-168

Valley Oak Savanna

Valley oak savannah on the north slopes of Laskey Mesa.

What a difference a week makes! At about 10:00 in the morning, when this photograph was taken, the temperature at a nearby weather station was a pleasant 78°F. Just a week before, the mid-morning temperature had been a blazing 104°F, and neighboring Woodland Hills had just set an all-time record high of 119°F!

The photograph is of valley oak savanna on the north slopes of Laskey Mesa in Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch). As mentioned in the posting Laskey Mesa Oak, this area was burned in the 2005 Topanga Fire. If you look closely, the condition of the trees varies widely. Some have full crowns; some partial crowns; and some are nearly bare.

Headed back on the Ahmanson “main drag,” I had done a keyhole loop through Cheeseboro Canyon, starting at the Victory trailhead. The 13 mile route is slightly shorter than the Bulldog Loop, and has less than half the elevation gain. Following several strenuous weeks, the idea was do some tempo and not too much climbing.

Here’s a Google Earth image and Google Earth KMZ file of a GPS trace of the loop, and links to trail maps for Upper Las Virgenes Open Space Preserve and Cheeseboro/Palo Comado Canyons.

Related post: Ahmanson Blue Oak