Frutidella
Genus of lichen
From Wikipedia, the free encyclopedia
Frutidella is a genus of lichen-forming fungi in the family Lecanoraceae.[1] It contains three species.[2] The genus was established in 1994 by Klaus Kalb to accommodate a species previously classified in the genus Lecidea. These lichens form thin crusts that often develop distinctive wart-like swellings packed with tiny granules, and they produce small, dome-shaped fruiting bodies with a characteristic blue-green sheen. Species of Frutidella typically grow on acidic substrates, including nutrient-poor soils in upland areas and the bark of trees.
| Frutidella | |
|---|---|
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Lecanorales |
| Family: | Lecanoraceae |
| Genus: | Frutidella Kalb (1994) |
| Type species | |
| Frutidella caesioatra (Schaer.) Kalb (1994) | |
| Species | |
|
F. caesioatra | |
Taxonomy
The genus was circumscribed in 1994 by Klaus Kalb to contain the species formerly known as Lecidea caesioatra.[3]
Description
Frutidella grows as a thin crust (crustose thallus) that breaks into discrete, tile-like patches (areoles) or develops conspicuous wart-like swellings. These swellings are packed with tiny, grain-like outgrowths that resemble miniature isidia; as they age the grains can crumble into a powder of soredia, providing a way for the lichen to spread vegetatively. Thallus colour ranges from greenish and grey to bluish or even nearly black, and a narrow white border (prothallus) may or may not be present. The photosynthetic partner is a single-celled green alga of the chlorococcoid type.[4]
The fruiting bodies of Frutidella are small, dome-shaped discs (biatorine apothecia). They sit directly on the thallus, sometimes half-hidden among the surface granules, and appear bluish black or dusted with a blue-grey frost (pruina) when damp. Unlike lichens that recycle thallus tissue to form a rim, these apothecia lack a thalline margin. Instead they are encircled by a true exciple—tightly packed hyphae that radiate like spokes and stay pale or yellowish, never becoming blackened. A crystalline pigment in the surface layer (epithecium) lends a bright blue-green sheen that does not react with potassium hydroxide solution. Beneath, the spore-bearing tissue (hymenium) contains slender, sparsely branched threads (paraphyses) and asci of the Lecanora type, each holding eight smooth, colourless, single-celled ascospores.[4]
Asexual reproduction takes place in minute, flask-shaped structures (pycnidia) that have a darkened tip and release very slender, thread-like conidia. Chemical studies using thin-layer chromatography have detected the secondary metabolite compounds sphaerophorin and thiophanic acid in most specimens, with isoarthothelin or asemone present occasionally.[4]
Ecology
Species of Frutidella favour acidic substrates. In upland and montane habitats they typically form crusts on nutrient-poor, low-pH soils, where they spread across cushions of mosses. Elsewhere they are mainly corticolous, colonising the acidic bark of trees.[4]
Species
As of July 2025[update], Species Fungorum (in the Catalogue of Life) accepts three species of Frutidella:[1]
- Frutidella caesioatra (Schaer.) Kalb (1994)
- Frutidella furfuracea (Anzi) M.Westb. & M.Svenss. (2017)
- Frutidella pullata (Norman) Schmull (2011)
