Thelocarpon
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| Thelocarpon | |
|---|---|
 | |
| Thelocarpon laureri | |
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Order: | Thelocarpales |
| Family: | Thelocarpaceae |
| Genus: | Thelocarpon Nyl. (1853) |
| Type species | |
| Thelocarpon laureri (Flot.) Nyl. (1854) | |
| Synonyms[1] | |
Thelocarpon is a genus of lichen-forming fungi in the family Thelocarpaceae.[2] The genus was established in 1853 by the Finnish lichenologist William Nylander, who distinguished it from related genera by its warted thallus structure, many-spored asci, and the distinctive violet-blue staining reaction of its fruiting body gel when treated with iodine. These tiny lichens form small, wart-like bumps on soil, wood, and plant debris, often covered with a distinctive bright yellow powdery coating. The genus includes about 30 species found worldwide, many of which produce unusually large numbers of ascospores—sometimes over 300 per spore sac.
The genus was circumscribed in 1853 by the Finnish lichenologist William Nylander. He established the genus to accommodate lichens with a whitish thallus composed of granular, clustered wart-like structures that sit above papillae and are perforated by mostly subtle pores, each containing a single pale, somewhat enlarged apothecium (fruiting body). He characterised the genus by its cylindrical-spindle-shaped, many-spored asci containing 24–80 or more ascospores per ascus, with the spores being pale yellow, ellipsoid, frequently single-celled. Nylander noted the presence of slender, very abundant paraphyses and observed that the genus was related to Endocarpon, commenting that it belonged to the tribe Endocarpeae. He distinguished Thelocarpon from the previously described Sphaeropsis by its different thallus characteristics, proposing the new genus name after noting that the mucilaginous hymenium was stained violet-blue by iodine and potassium iodide.[3]
In a 1966 monograph of the genus, George Salisbury treated Thelocarpon in a relatively narrow sense, accepting 13 species and reviewing several generic names that had at various times been used for segregates now associated with the genus, including Thelococcum, Athelium, and Alinocarpon. He also noted that the genus had long been difficult to classify, having been placed by different authors near the Hypocreaceae, the Acarosporaceae, or in its own family, Thelocarpaceae. Salisbury had earlier divided the genus into sections based on the presence or absence of an algal sheath, but in his 1966 revision he abandoned that arrangement, arguing that it relied too heavily on degree of lichenization rather than natural relationships. He instead organized the species chiefly by the morphology of the paraphyses together with the development of the algal sheath.[4]