Circinaria arida
| Circinaria arida | |
|---|---|
| Scientific classification | |
| Kingdom: | Fungi |
| Phylum: | Ascomycota |
| Class: | Ascomycetes |
| Order: | Pertusariales |
| Family: | Megasporaceae |
| Genus: | Circinaria |
| Species: | C. arida |
| Binomial name | |
| Circinaria arida | |
Circinaria arida (pebble ball lichen) is a .5-6 cm, light olive-brown custose lichen that grows on rock, often like a cluster of little light brown to olive balls growing on pebbles, in the southwestern deserts of North America.[1][1] It is also found in Eurasia, and arid parts of North America from the southern Great Plains and Midwest to California.[1][2] It is warty (verrucose)with the warts sometimes cracking apart areolate.[2] The warts or areolas have angular to rounded sides.[2] The 0.2-2.3 mm, convex to flat-topped areolas are separated by deep fissures that may be as deep (0.1-2 mm) as the areaola is wide, so the lichen often appears to be made of clusters of little balls crammed up next to each other, although the areolas are sometimes isolated.[2] In California it is commonly found growing on pebbles.[1] Each areola has a single sunken black, dust covered (pruinose) fruiting body (apothecium) with a white rim.[1] A thin strip of prothallus sometimes is at the outer edge, forming a narrow dark zone (fimbriate).[2] The similar Aspicilia desertorum has a white pruina (dusty coating) on the apothecia.[2] A thin strip of prothallus sometimes is at the outer edge, forming a narrow dark zone (fimbriate).[2] It is negative for lichen spot tests, I-, K-, P-, C-.[1]