Borrego Clouds (April 2012)

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Anza-Borrego

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Scenic Clouds Over Anza-Borrego Area

© W.P. Armstrong 14 April 2012

Images Taken With Sony DSC-T9, Nikon D-40X, and Nikon D-90.

Lake Henshaw, Montezuma Valley & Borrego Valley

Desert dandelion (Malacothrix californica) & goldfields (Lasthenia gracilis).

Scarlet bugler (Penstemon centranthifolius).

Hummingbird resting on cat's claw acacia.

Borrego Valley Looking Toward Coyote Mountain & Santa Rosa Mts.

Coyote Creek area looking north toward Santa Rosa Mountains.

A Rainbow During The Storm Over Borrego Palm Canyon

Rainbow in Borrego Palm Canyon.

Rainbow Enhancement By Landscape Photographer Jack Quintero

Dark Cryptobiotic Soil Lichens

The U.S. Penny Used For Size Relationship Is 19mm In Diameter.

Black cryptobiotic soil lichen, mostly Collema (possibly C. coccophorum).

The black, granular, tarlike area in center is an isidiate, cyanolichen of the genus Collema (possibly C. coccophorum). It is surrounded by the brown, scalelike squamules of Placidium lacinulatum. In Placidium, the spore-bearing perithecia are embedded in the thallus (white arrow). Magnification 10x.

Green algal cells inside the thallus of Placidium. The photobiont is a species of Myrmecia (Chlorophyta). The similar-appearing Peltula has unicellular cyanobacteria for its photobiont. Magnification 400x.

Another Species Of Cryptobiotic Soil Lichen: Peltula obscurans var. hassei
Although squamules appear similar, Peltula is very different from Placidium

While walking along the alluvial slope west of the Anza-Borrego Park Visitor Center, I noticed a black cryptobiotic soil lichen in the ravines. I thought it was the usual species (Collema or Placidium), but to my surprise it was a different genus (Peltula). This species has a squamulate thallus composed of scalelike sections called squamules. In the center of some squamules is a sunken apothecium. The thallus of Placidum is similar, except the squamules contain multiple embeddded perithecia, each with a minute opening (pore). Unlike the green alga photobiont in Placidium, the photobiont in Peltula is a cyanobacterium. The other common, dark cryptobiotic lichen in Anza-Borrego (Collema) also has symbiotic cyanobacteria.

Cryptobiotic soil lichen (Peltula), possibly P. obscurans var. hassei. Some squamules appear pubescent with minute silvery hairs. These may be fungal hyphae, possibly a mold. The lichen thallus varies from dark olive to reddish-brown, depending its moisture content.

Anacystis?

According to Lichen Flora of the Greater Sonoran Desert Region (Volume 1) by Tom Nash III, et al. (2002), the primary photobiont of Peltula is the unicellar cyanobacterium Chroococcidiopsis or Myxosarcina. In Lichens of North America by I.M. Brodo, S.D. Sharnoff and S. Sharnoff (2001), the cyanobacterial photobiont is listed as Anacystis. Chroococcidiopsis is described as coccoidal in most references; however, the bacterial cells I observed inside Peltula were oval. Each cell was surrounded by a transparent sheath that appeared like a thin, white border. On a microscope slide under under 1,000X magnification there were numerous oval cells with a faint blue-green color. I did not see the green algal cells of Placidium or the nostoc-like filaments of cyanobacteria found in Collema.

Highly magnified view of cyanobacteria inside Peltula squamule using oil immersion and 1,000x magnification. The oval cells are approximately 3.0 µm long and 1.0 µm wide. Their shape resembles images of Anacystis on the Internet. The transparent cellular sheath appears like a thin white border. These bacterial cells are smaller than human red blood cells (7.5 µm in diameter).

Chroococcidiopsis is one of the most primitive cyanobacteria (blue-green algae) known. It is a photosynthetic bacteria known for its ability to survive harsh environmental conditions, including both high and low temperatures, desiccation, ionizing radiation, and high salinity. It is known as an extremophile and it is one of the species NASA is studying for possible farming in greenhouses on Mars. The colonies could provide oxygen and fresh food for astronauts. Perhaps genes from these bacteria could be introduced into other plants, thus making them resistant to environmental extremes.

Cryptobiotic Crust: Lichens, Liverworts and Mosses
List Of Lichen Images Featured On Wayne's Word
More Soil Lichens Forming A Cryptobiotic Crust
Lichen Crust Terminology & Desert Varnish

Some Desert Wildflowers