Crustose Lichen Photos (Cont.)
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Crustose Rock, Soil & Bark Lichens

Left: Diploschistes muscorum, a grayish-white soil lichen at Torrey Pines State Park in San Diego County, California. This crustose lichen produces numerous, crowded, cup-shaped apothecia. Right: Microscopic view (400x) of the apothecia of Diploschistes muscorum showing several faint, saclike asci (upper left) and four brown spores. The large spores are divided into many sections, a condition referred to as muriform. This is somewhat like the squares of a Hershey's chocolate bar. Although originally identified as D. scruposus using Lichens of California by M.E. Hale and M. Cole (1988), this soil lichen is probably D. muscorum.

Diploschistes muscorum, a crustose soil lichen that is very similar to D. scruposus. It typically grows on soil (terricolous) and may even grow over mosses (muscicolous) and other lichens (lichenocolous). The grayish-white thallus contains numerous, crowded, cup-shaped apothecia. The brown muriform spores are about 35 micrometers long, four spores per ascus. D. scruposus may have 4-8 spores per ascus and typically grows on rock (saxicolous). The apothecia of D. scruposus are variable, from urn-shaped (urceolate) to slightly perithicioid (perithecia-like). The phycobiont of both species is Trebouxia, a unicellular green alga found in many species of lichens. Both D. muscorum and D. scruposus are K+ yellow to red and Cl+ red. They both contain diploschistic, lecanoric and orsellinic acids. View of spore and algal cells taken with Sony digital camera through compound microscope at 1000x.

Diploschistes muscorum, a crustose soil lichen. One drop of sodium hypochlorite or household bleach (NaClO) added to the thallus causes an immediate red coloration. This indicates that the lichen is Cl+ red. It is also K+ yellow because the gray thallus turns yellow when a drop of NaOH (lye) is added.

Diploschistes muscorum growing over a green moss and another lichen Cladonia chlorophaea (red arrow) in the Merriam Mountains of northern San Diego County. The closely related D. scruposus does not exhibit this muscicolous and lichenocolous behavior.

Diploschistes scruposus, a saxicolous lichen growing on a granitic boulder at the San Diego Wild Animal Park. The similar D. muscorum typically grows on soil, other lichens and mosses. The inset photo shows two large, muriform spores and a cell of the phycobiont Trebouxia. The spores are slightly larger than those of D. muscorum (up to 40 µm long), and may occur 4-8 per ascus. Spores of D. muscorum generally do not exceed 30 µm in length and occur 4 per ascus. Two additional rock lichens with a similar gray-white thallus are Dimelaena radiata and Thelomma mammosum; however, the spores of these latter two species are very different. Dimelaena radiata has brown 2-celled spores (8 per ascus), and Thelomma mammosum produces a loose mass of black single-celled spores called a mazaedium. The black spore mass often extends out of the apothecia.

Another Species Of Diploschistes In The Cuyamaca Mountains


Haematomma lapponicum (Ophioparma lapponica): A crustose soil lichen that grows on the tundra of northern Alaska's Brooks Range. The red structures resembling blood blisters are apothecia.


Psora decipiens, a squamulose soil lichen that appears in Anza-Borrego desert during wet years. It also grows on granitic soils in the coastal mountains of San Diego County. The thallus is composed of scalelike squamules. Each squamule contains black, marginal apothecia (black arrow).


Icmadophila ericetorum, a seldom-seen crustose lichen that typically grows on rotten logs in moist coniferous forests of northern California, Oregon and Washington. The moist, greenish thallus bears numerous pinkish-white or flesh-colored apothecia. It is affectionately known by some lichen hunters as "fairy barf," a rather uncomplimentary name for such an attractive little lichen.


Ochrolechia oregonensis, an interesting crustose lichen that grows on the bark of cone-bearing trees on Palomar Mountain in San Diego County. The moist, greenish thallus produces numerous pinkish-tan or yellowish apothecia. During the dry months the thallus appears gray rather than green. O. subpallescens typically grows on the bark of deciduous trees. In medieval Europe, the red dye called "cudbear" was obtained from another species of Ochrolechia (O. tartarea).


Pertusaria subambigens, a greenish-gray, crustose bark lichen that commonly grows on the trunks of conifers in the Coast and Cascade Ranges of Oregon. It is also listed as P. ambigens is some field guides. The apothecial disks are pruinose (powdery or frostlike) and ragged, with concentrically arranged marginal tissue. With some imagination they resemble minature flowers.


Closeup view of the trunk of Mexican logwood or palo de brasil (Haematoxylum brasiletto). The grayish-white patches are produced by the crustose bark lichen Graphis (possibly G. scripta). A. The black apothecia are about 0.2 mm wide and 2-3 mm ling, straight to curved or slightly branched. B. The lower edge of the gray, crustose thallus. C. Bark lenticels (small circular openings in the bark for gas excange). This remarkable shrub was photographed in southern Baja California, between Cabo San Lucas and La Paz.


The deeply fluted, corrugated trunk of Mexican logwood or palo de brasil (Haematoxylum brasiletto) is similar to Belize logwood. This species has a remarkable distribution from desert hillsides and arroyos of Baja California and Sonora, Mexico, extending south through tropical dry forests of Oaxaca, Guatemala, Costa Rica and Colombia. The flowers are typical of the pea subfamily Caesalpinioideae with five spreading petals, unlike the typical pea blossoms of subfamily Papilionoideae. The heartwood dye is used for cottons and wool, and as a pink coloring for toothpaste and mouthwash. The gray patches on the bark are caused by Graphia stricta, an interesting crustose lichen.

See The Logwoods Of Belize And Mexico


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