Category Archives: nature|botany

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Winter Bloom

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A California fuchsia in deep shade blooming in December in the Santa Monica Mountains.

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.

nature, nature|botany, nature|wildflowers, trails, trails|smmc open space

Coyote Candy

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Hollyleaf cherry (Prunus ilicifolia) on the Chumash Trail

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

nature, nature|botany, photography

Thistledown on Ragweed

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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

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Hexagonal Close Packing

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Hexagonal close packing of the disk florets of an immature Sneezeweed blossom.

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

nature, nature|botany, nature|insects, nature|wildflowers, photography, photography|insects, photography|wildflowers

Mariposa Yellow

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Clubhair mariposa lily (Calochortus clavatus).

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 species of Perdita (Andrenidae). These bees were found on several of the mariposa blossoms along the trail. They were usually near 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

Google search: $g(mariposa lily)

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All in Which Family?

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Indian warrior (Pedicularis densiflora) on the Backbone Trail in the Santa Monica Mountains.

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.

Indian warrior (Pedicularis densiflora) resembles two other wildflowers you might see along a Southern California trail — Indian paintbrush (Castilleja affinis) and Owl’s clover (Castilleja exserta). All three are related root parasites that obtain water and nutrients from their host, but also contain chlorophyll and can photosynthesize carbohydrates.

It seems this characteristic would be of value in a climate where seasonal rainfall is highly variable, extending the parasitic plant’s access to water.

Recent genetic analysis has revealed that Pedicularis and Castilleja are related to plants in the Broomrape family (Orobanchaceae), rather than those in the Figwort family (Scrophulariaceae), in which they have been classified. This was a somewhat unexpected result because one of the distinguishing characteristics of Orobanchaceae had been the lack of chlorophyll.

The photograph was taken on the Backbone Trail on the run described in A Long Run Kind of Day.

Technical References:

The Physiology of Plants Under Stress By Erik T. Nilsen, David M. Orcutt

PLANTS THAT LIKE HOSTS By Toni Corelli

Phylogeny of the parasitic plant family Orobanchaceae inferred from phytochrome A[1]

Jonathan R. Bennett and Sarah Mathews

Google search: $g(parasites), $g(Orobanchaceae), $g(chlorophyll), $g(phylogeny), $g(genetics)