Saturday, I'd run in the Malibu Creek Challenge 22K. Today I Wanted to do something low key. Not too long, not too steep, but still a run that would work out the kinks that follow a race. I finally settled on the Secret Trail to Calabasas Peak, a 4.25 mile course with an elevation gain/loss of around 750 ft.

The low clouds and fog that surged into the Santa Monica Mountains on Saturday had returned during the night. The mustard and monkeyflower along the trail were soaked with dew, and now, so was I. Running felt good, and the two or so miles to the peak passed quickly.

The sun had nearly burned through the morning overcast, and just below the summit of Calabasas Peak, the bright yellow flowers of a Spanish broom seemed to capture and concentrate the subdued sunlight.

Spanish broom (Spartium junceum) is a twiggy, green shrub that originated in the Mediterranean. It is common at lower elevations of our local mountains. According to the California Invasive Plant Council it was introduced as an ornamental in San Francisco in 1848, and planted along highways in Southern California in the 1930s. Its color and fragrance are distinctive.

Prior to running the Inca Trail we did an acclimatization run at 11,000 ft on the altiplano near Chinchero. The very first flower I saw on the run was a Spanish broom! This suggests that Spanish broom could spread to higher elevations of the San Gabriel Mountains, particularly if climate change results in more arid conditions.

Some related posts: Peru Running, Secret Trail to Calabasas Peak, Tapia Bound

As we've seen this Winter, it is the norm for Southern California's weather to be abnormal. Cool, wet weather in December was followed by weeks of warm, dry weather in January. It is hard to predict when it will be wet and when it will be dry. Especially if you are a plant.

This photograph of a shooting star (Dodecatheon clevelandii ssp. patulum) is from early February, when the weather was dry. Droplets of moisture can be seen clinging to the interior walls of the seed capsules. These climate moderated capsules helps ensure that the plant will produce viable seeds, even if an extended period of dry weather should occur after the plant blooms.

Deep in shade on a north-facing chaparral slope, this California fuchsia (Epilobium canum ssp. canum) has not savored direct sunshine for weeks. Overnight temperatures in the Santa Monica Mountains have dropped to freezing several times this Winter, and frosts have been common. But this hardy plant continues to bloom.

According to the Jepson Manual this subspecies ranges up to about 5000 ft. in elevation, and the parent species up to about 10,000 ft. As a genus, Epilobium is well represented by species that grow at higher latitudes and elevations, and must have developed adaptations that help it flourish in cooler climes.

From a run on the Old Boney Trail on December 27, 2008.

Sometimes growing as large as a supermarket cherry, the sweetish, thin-pulped fruit of hollyleaf cherry (Prunus ilicifolia) is a favorite snack of coyotes.

These are on the Chumash Trail in Rocky Peak Park. This is the first year since the 2003 Simi Fire that there has been a sizable hollyleaf cherry crop along the trail.

It is commonly reported that an "acid treatment" in the digestive tract of a coyote or bird is required for germination. However, according to the University of Texas Native Plant Information Network Native Plant Database, fresh seeds require no treatment.

Related post: Holly-leaved Cherry

Adjacent to Las Virgenes Creek, not far from the cattails of Linear Green, is a sizable plot of western ragweed. On a recent run I noticed several tufts of fluff caught on the ragweed and backlit by the afternoon sun.

Investigating, I found the source of the tufts about 15 yards away -- a patch of bull thistle -- an invasive weed that is found throughout the U.S.

Like a dandelion, bull thistle seeds are attached to a downy pappus, and can be dispersed by wind. The rate at which these plumed seeds fall through still air is quite low -- less than 1.5 ft/sec. This is slower than the minimum sink rate of a high performance sailplane. For a given plant height, the lower the sink rate, the farther the seed can potentially be dispersed from the parent plant.

Even though the plumed seed of bull thistle (Cirsium vulgare) is much larger and heavier than a dandelion's familiar tuft, it is reported to have about the same ratio of plume area to seed weight. This is a key factor affecting the sink rate. However, the bull thistle's seed is reported to sink at about a 15% slower rate than the dandelion's. This may be attributable to aerodynamic and structural advantages of the secondary branches found in the plume of the bull thistle, but not in the dandelion's.

Related technical papers:

Diaspore Size, Shape, and Fall Behavior in Wind-Dispersed Plant Species
Glenn R. Matlack
American Journal of Botany, Vol. 74, No. 8 (Aug., 1987), pp. 1150-1160
Botanical Society of America

The Aerodynamics of Plumed Seeds
D. F. Greene and E. A. Johnson
Functional Ecology, Vol. 4, No. 1 (1990), pp. 117-125
British Ecological Society

There are some imperfections, but generally the unopened disk florets comprising the head of this immature sneezeweed blossom are arranged so that each floret is surrounded by six other florets. This is an example of hexagonal close packing, and is probably the most dense arrangement of florets that can be achieved in this spherical flower head.

The photograph of the Bigelow's sneezeweed (Helenium bigelovii) was taken on an out and back run on the Pacific Crest Trail from Vincent Gap to Little Jimmy Spring during July 2007.

Related post: Bigelow's Sneezeweed & Bee

There is yellow, and then there is the YELLOW of the mariposa lily, Calochortus clavatus. Remarkable in its brightness and purity, its yellow is one of the most intense and vibrant concentrations of color I have seen in the chaparral.

It is relatively uncommon, and this is one of a few seen along trails in Rocky Peak Park, and the Simi Hills. Of the varieties listed in the Jepson Manual, this appears most similar to the slender mariposa lily (Calochortus clavatus var. gracilis).

The insect emerging from the flower is a small bee -- probably a sweat bee (Halictidae). These bees were found on several of the mariposa blossoms along the trail. They were usually busy slurping nectar from the gland near the base of each petal, and partially hidden by the club-like hairs that gives the species its name.

From a run earlier this week in Rocky Peak Park.

Related posts: Mountain Mariposa, Plummer's Mariposa Lily

Technorati Tags: mariposa lily

Indian warrior's varying tones of carmine contrast sharply with its lush green leaves and create a striking combination of colors when seen along a trail. Surprisingly, it is the green of its leaves that is one of its interesting features.

Updated 03/13/08.

My run of the "keyhole loop" at Ahmanson Ranch started out as a tempo run -- not so much as being part of a rigorous training program, but because of a dead battery in my car remote. It felt good to push the pace a bit.

Part way through the loop, running up a short hill into the sun, I was struck by a repetitive pattern of backlit leaves in the new growth on and alongside the road. Like little green satellite dishes, hundreds of the round leaves of mallow (Malva neglecta) were facing directly into the late afternoon sun.

Mallow (Malva spp.) is an invasive plant from the Mediterranean area that has flourished in Southern California's Mediterranean climate. In most years, it is very common. I've run and hiked past thousands of these plants, but never noticed this synchronicity.

Tracking the sun makes sense. Our climate has an extremely variable and relatively short growing season. A plant that maximizes its intake of solar energy and growth by orienting its leaves toward the sun would have an advantage over a less adaptable species. This is probably one of the reasons mallow is such a successful invasive. Another invasive that grows alongside mallow, black mustard, also appears to exhibit heliotropism as it is growing. It creates a rosette of leaves facing into the sun by raising leaves on the side of the stalk away from the sun, and lowering leaves on the side of the stalk toward the sun.

From a run during the week at Ahmanson Ranch -- now Upper Las Virgenes Canyon Open Space Preserve.

Technical papers:

Diaphototropic Movement of the Leaves of Malva Neglecta
H. C. Yin
American Journal of Botany, Vol. 25, No. 1 (Jan., 1938), pp. 1-6

HELIOTROPISM AND WATER AVAILABILITY EFFECTS ON FLOWERING DYNAMICS AND SEED PRODUCTION IN Macroptilium lathyroides
ARMANDO MARTINS DOS SANTOS, LUIS MAURO GONÇALVES ROSA, LUCIA BRANDÃO FRANKE, CARLOS NABINGER

Listed by the California Native Plant Society as being rare, threatened, or endangered, Santa Susana tarweed (Hemizonia minthornii) can be found where sandstone outcrops of the Chatsworth formation occur, such as in the Santa Susana Pass area in the Simi Hills.

This photograph was taken on a run at Sage Ranch on October 1, 2007.

Maybe it's the result of record low rainfall, or the 2005 Topanga Fire, or a combination of the two -- there has been a dramatic increase in the amount of tumbleweed (Salsola tragus) along the dirt roads in Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch).

Like black mustard, and milk thistle, tumbleweed is an invasive plant. According to UC IPM Online tumbleweed is native to southeastern Russia and western Siberia and was first introduced into the United States (South Dakota) in 1873.

The photograph of the tumbleweed flower was taken on a run at Ahmanson Ranch on October 3, 2007.

Some related posts: Dealing With Drought, Milk Thistle Seed Heads, Curly Dock

Who hasn't pondered the intriguing network formed by the interconnected veins of a leaf? Like many apparently complex self-organized structures, there is a recognizable pattern, but the basis of the pattern is difficult to grasp.

Remarkably, research published in 2002 (S. Bohn et al., Phys. Rev. E, June 2002.) found that there is a simple relationship governing the angles between vein segments in the leaves of dicotyledons, and that this relationship is universal. The study also found that the observed vein angles can be reproduced using a simple force model.

Numerical analysis of leaf scans revealed that the angles between vein segments are directly related to the thickness of the segments. When the vein sizes are similar, the connection appears to form a three-way junction with the angle between the veins about 120 degrees. If the vein sizes are dissimilar, with one much larger than the other, the smaller vein joins the larger at about a 90 degree angle.

The photograph is of a leaf of a Fremont cottonwood (Populus fremontii) along Las Virgenes Creek in Upper Las Virgenes Canyon Open Space Preserve. It was taken on a run from the Victory trailhead on May 16, 2007.