Diorygma
From Wikipedia, the free encyclopedia
| Diorygma | |
|---|---|
 | |
| Diorygma antillarum found in Fakahatchee Strand Preserve State Park, Florida | |
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Graphidales |
| Family: | Graphidaceae |
| Genus: | Diorygma Eschw. (1824) |
| Type species | |
| Diorygma tinctorium Eschw. (1824) | |
| Species | |
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See text | |
| Synonyms[1] | |
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Diorygma is a genus of lichen-forming fungi in the family Graphidaceae. The genus was circumscribed by Franz Gerhard Eschweiler in 1824.[2] Species of the genus are widely distributed in tropical and subtropical regions of the world. These lichens form paint-like crusts on bark and rock that range from chalky white to light green, with elongated, pencil-like slits containing their spores that may flex and branch across the surface. The genus was established in 1824 for tropical script lichens with large, many-celled spores, but molecular studies in the 2000s and 2010s expanded it significantly by transferring species from other genera and revealing new diversity.
The name Diorygma was coined by Franz Gerhard Eschweiler in 1824 for a group of neotropical script lichens in the family Graphidaceae that have large, many-celled (muriform) spores and a thin, naked hymenium.[2] Elias Fries accepted the genus in 1825—likening it to what is now Arthonia—but made no additional combinations. Eschweiler himself broadened the concept in 1833 by adding several species that subsequent work has reassigned to Fissurina and Platythecium. Towards the end of the nineteenth century, Johannes Müller Argoviensis erected the genus Graphina for muriform-spored taxa, retaining a handful of Diorygma species within his sections Platygraphina and Platygrammina, thereby narrowing the scope of Eschweiler's original taxon.[3]
Interest in the group revived in the twentieth century. Dharani Dhar Awasthi and Mamta Joshi, while revising Helminthocarpon in 1979, recognised that these lirellate lichens formed a discrete lineage, but instead of resurrecting Eschweiler's name they introduced Cyclographina. In a comprehensive monograph of 2002, Bettina Staiger restored Diorygma for this assemblage and, on the basis of its rather unusual tissue organisation, suggested that it might fall outside the core Graphidaceae. Subsequent molecular analyses have confirmed that Diorygma does indeed belong within that family and have expanded its limits to include species with either single-spored, muriform asci or with spores divided only by transverse walls.[3]
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