| Byssoloma | |
|---|---|
| | |
| Byssoloma leucoblepharum | |
| Scientific classification | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Lecanorales |
| Family: | Pilocarpaceae |
| Genus: | Byssoloma Trevis. (1853) |
| Type species | |
| Byssoloma leprieurii Trevis. (1853) | |
| Species | |
See text | |
| Synonyms [1] | |
Byssoloma is a genus of leaf-dwelling lichens in the family Pilocarpaceae. [2]
The genus was circumscribed by the Italian botanist Vittore Benedetto Antonio Trevisan de Saint-Léon in 1853. [3]
Species in genus Byssoloma form crustose, effuse (spreading) lichens that lack a cortex (outer protective layer). Their photobiont , or photosynthetic partner, is of the chlorococcoid type, a form of green algae. [4]
The apothecia (fruiting bodies), are sessile (directly attached to the thallus without a stalk) and approximately circular in shape. They lack a thalline margin (a rim formed by the lichen thallus) and possess a true exciple , which is a layer of loosely arranged hyphae that can appear hairy or web-like ( tomentose - arachnoid ) in some species. The hymenium, the spore-bearing tissue, reacts with iodine to turn blue (I+ blue). The hamathecium , consisting of paraphyses (filamentous support structures), is unbranched or slightly branched and not or only slightly thickened at the tips. [4]
The hypothecium , a layer beneath the hymenium, is dark red-brown and may turn purple when treated with potassium hydroxide (K) solution in European species. The asci, which are the sac-like structures where spores develop, typically contain eight spores. They have thick walls and a blue-staining apical dome with a darker blue tubular ring structure and an amyloid (starch-like) gelatinous coat. [4]
The ascospores are three-septate (having three internal partitions), colourless, and found in European species. Asexual reproductive structures, the pycnidia, are also sessile and roughly spherical, usually covered by a layer of loosely interwoven hyphae. The conidiophores (spore-producing cells) are unbranched, forming flask-shaped, bacillar (rod-like), or ellipsoidal conidia (asexual spores) that are constricted in the middle. [4]
Chemically, argopsin, a secondary metabolite (lichen product), is sometimes detected in one species, but otherwise, Byssoloma lacks lichen products. [4]
As of July 2024 [update] , Species Fungorum accepts 39 species of Byssoloma. [5]