Diplotomma venustum
| Diplotomma venustum | |
|---|---|
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Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Caliciales |
| Family: | Caliciaceae |
| Genus: | Diplotomma |
| Species: | D. venustum |
| Binomial name | |
| Diplotomma venustum Körb. (1860) | |
| Synonyms[1] | |
|
List
| |
Diplotomma venustum is a species of saxicolous (rock-dwelling) crustose lichen in the family Caliciaceae.[2] It is widely distributed, having been recorded from all continents, where it grows on calcareous rocks.[3]
Taxonomy
[edit]The lichen was first formally described as a new species by German lichenologist Gustav Wilhelm Körber in 1860. Körber's Latin diagnosis emphasised the firmly attached, granular-powdery thallus with very fine wrinkling, and the mostly solitary apothecia that are immersed in the thallus when young but become convex with a black disc. He characterised the colourless ascospores as ellipsoidal to spindle-shaped with 4 cross-walls (4-septate) and noted they turn sooty-brown with age. The species was described from limestone and dolomite rocks in mountainous regions of central Europe, including collections from Germany, Austria, and the Carpathian Mountains.[4]
Description
[edit]Diplotomma venustum forms a crust-like thallus that is tightly attached to the substrate (crustose) and often broken up by numerous irregular cracks and fissures (rimose). The margin may become weakly lobed. A thin black border (the prothallus) is sometimes visible around the thallus. The upper surface is chalky white, grey, or ochre-tinged and lacks powdery vegetative propagules. The interior (medulla) is white and contains abundant needle-shaped crystals of calcium oxalate; these crystals also generate the fine white pruina that commonly dusts the fruiting discs. Under ultraviolet light the thallus does not fluoresce (UV−), and standard spot tests on the thallus and medulla are negative in North American material (K−, P−, C−); outside North America, some collections react K+ (yellow turning red) and P+ (yellow-orange), reflecting the presence of norstictic and connorstictic acids in the medulla.[5]
References
[edit]- ↑ "GSD Species Synonymy. Current Name: Diplotomma venustum Körb., Parerga lichenol. (Breslau) 2: 179 (1860)". Species Fungorum. Retrieved 16 October 2025.
- ↑ "Diplotomma venustum Körb". Catalogue of Life. Species 2000: Leiden, the Netherlands. Retrieved 16 October 2025.
- ↑ Kantvilas, Gintaras. "Diplotomma". Flora of Tasmania Online. Hobart: Tasmanian Herbarium, Tasmanian Museum and Art Gallery. Retrieved 16 October 2025.
- ↑ Körber, Gustav Wilhelm (1865). Parerga lichenologica. Ergänzungen zum Systema lichenum Germaniae (in German). Vol. 2. Breslau: E. Trewendt. p. 179. doi:10.5962/bhl.title.87905.
- ↑ Nash III, Thomas H.; Gries, Corinna; Bungartz, Frank, eds. (2007). "Romjularia". Lichen Flora of the Greater Sonoran Desert Region. Vol. 3. Tempe: Lichens Unlimited, Arizona State University.