Lathagrium
From Wikipedia, the free encyclopedia
| Lathagrium | |
|---|---|
.jpg) | |
| Lathagrium auriforme | |
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Peltigerales |
| Family: | Collemataceae |
| Genus: | Lathagrium (Ach.) Gray (1821) |
| Type species | |
| Lathagrium undulatum | |
| Synonyms | |
| |
Lathagrium is a genus of lichen-forming fungi in the family Collemataceae.[1] It has 10 species of gelatinous lichens.[2] Species in this genus typically grow on calcareous rocks, often amidst mosses, but can also be found on siliceous or serpentine rocks, mortar, or soil.[3]
Lathagrium was introduced by Erik Acharius in 1810 as a section of Collema,[4] and raised to generic rank by Samuel Gray in 1821.[5] In their modern re-appraisal of the jelly-lichens (Collemataceae), Otálora and colleagues fixed the name by designating Lathagrium furvum (≡ Lichen fuscovirens With.) as lectotype. They also note that Massalongo's later spelling "Lethagrium" refers to the same name and is merely an orthographic variant that fell out of use; both Acharius and Gray had originally included several unrelated species under the heading.[6]
The molecular classification places Lathagrium as the well-supported sister lineage to Scytinium. In delimiting the genus, the authors emphasise features that separate it from its near relatives: Lathagrium species are medium- to large-foliose jelly lichens lacking a true cortex and bearing mainly submuriform spores—i.e., spores divided by cross-walls and a few lengthwise walls so they appear brick-like under the microscope—and they are chiefly rock- or soil-dwelling (saxicolous/terricolous), whereas Collema is mostly bark-dwelling (corticolous). They also distinguish Lathagrium from Enchylium by lobe and apothecial rim (proper exciple) morphology: Lathagrium has swollen, pleated (plicate) lobes, while Enchylium has concave, undulate lobes that are never pleated.[6]
In practical taxonomy, Lathagrium is treated as comprising the Cristatum and Durietzii groups as previously described by Gunnar Degelius; the latter were not sampled in the phylogeny but are judged to belong here based on habit and habitat. To bring names into line with this circumscription, the authors effected ten new combinations transferring species from Collema into Lathagrium.[6]
