Excerpts from Jim Conrad's
from the January 19, 2014 Newsletter issued from the Frio Canyon Nature Education Center in the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
One of our most handsome and easy-to-identify lichens turned up this week on a dead Texas Liveoak branch. It was a "fruticose" lichen, which means that it had definite stems, as opposed to "crustose" types that form more or less solid sheets growing over surfaces, or "foliose," which are like leaves lying flat on a surface. Our fruticose lichen was a small one, only about an inch tall (2.5cm). Above, you can see its branched, grayish stems and its spectacular apothecia, or fruiting cups, distinctively fringed along their cup margins with eyelash-like cilia, and with the spore-producing cup surfaces a bright yellow-orange.
With such flashy features our lichen was easy to identify as TELOSCHISTES CHRYSOPHTHALMUS, often known as the Golden-eye Lichen. Golden-eye Lichens occur spottily worldwide, except not in Asia, and are most frequent in Mediterranean climates in both hemispheres. In North America it seems limited to the central area from Manitoba south through the Plains, through Texas and Louisiana, and southward.
On the south coast of England, Golden-eye Lichens were present over a hundred years ago, then became extinct, and now are recolonizing at a good rate, apparently as spores blow across the English Channel from France. Global warming isn't thought to be behind this, since the lichen was present earlier during much cooler times. General consensus is that probably the species is particularly vulnerable to air pollution. Recent environmental laws have cleared the air somewhat, so the lichens are returning.
Of course lichens are "composite organisms" composed of a species of fungus whose hyphae intermingle with cells of an alga and/or cyanobacterium. In the Golden-eye Lichen's case, the photosynthesizing partner, or "photobiont," is the single-celled green algae Trebouxia, which combines with several species of fungus to produce various lichen species. You might be interested in seeing what Tebouxia algal cells look like enmeshed with fungal hyphae at http://www.bioref.lastdragon.org/Chlorophyta/Trebouxia.html.