Bactrospora

''Bactrospora'' is a genus of lichen-forming fungi of uncertain familial placement in the order Arthoniales. These lichens grow as thin crusts on tree bark in shaded, humid environments and are distinguished by their unusually long, needle-like spores that often break apart into smaller pieces. The genus includes 24 species found worldwide, particularly in tropical and temperate forests where they help form part of the diverse bark-dwelling lichen community.

Taxonomy

The genus was circumscribed by the Italian paleobotanist and lichenologist Abramo Bartolommeo Massalongo in 1852. Massalongo distinguished ''Bactrospora'' primarily by its distinctive spore characteristics: rod-shaped spores that divide into two-celled, elliptical segments—combined with polysporous asci containing 18–20 spores. He established ''B. dryina'' as the type species based on material collected from Germany.

Description

''Bactrospora'' forms a thin, crust-like thallus that either sits on the bark surface or sinks slightly into it. The crust is usually continuous and even, though older colonies may crack into an irregular mosaic, and its surface can appear scurfy or powdery. Because a true —the protective outer skin found in many lichens—is missing, the fungal layer merges directly with the algal partner. The is the orange-tinged green alga '' Trentepohlia'', whose cells become visible and stain the thallus orange when the surface is gently scratched. A (an outer fringe of pure fungal tissue) is poorly developed and often escapes notice. No characteristic lichen products have been detected with thin-layer chromatography.

The fruit bodies of ''Bactrospora'' are tiny, black to black-brown (apothecia) that sit on the thallus without a rim of surrounding tissue (a ). Their own wall, the , stays conspicuous; it is dark red-brown at the edge but becomes paler further in, and a drop of potassium hydroxide solution (KOH) turns this pigment an olive-black. Internally, the clear (hyaline) hymenium contains stout, sparsely branched whose tips interlink to form a cap () ranging from pale to dark red-brown. Each ascus follows the ''Opegrapha''-type pattern: its wall splits apart when the spores are released, and an iodine staining may reveal a faint blue dome over the tiny ocular chamber at the apex.

Ascospores are elongated, thin and needle-like, divided by dozens of internal walls. Mature spores frequently break up into smaller spherical or short-cylindrical part-spores, so older asci often appear to contain many more than the original eight. Asexual reproduction occurs in flask-shaped pycnidia embedded in the thallus; these produce colourless, rod-shaped conidia that escape through a dark-brown pore whose pigment also turns green-black in KOH. ''Bactrospora'' is usually corticolous, colonising the bark of trees in shaded, humid habitats, and can be told apart from related genera such as '' Lecanactis'' and '' Cresponea'' by its extremely multiseptate, fragmentation-prone spores.

Species

, Species Fungorum (in the Catalogue of Life) accepts 24 species of ''Bactrospora''.

*'' Bactrospora angularis''
*'' Bactrospora arthonioides''
*'' Bactrospora brevispora''
*'' Bactrospora carolinensis''
*'' Bactrospora cascadensis''
*'' Bactrospora corticola''
*'' Bactrospora dryina''
*'' Bactrospora flavopruinosa''
*'' Bactrospora granularis''
*'' Bactrospora homalotropa''
*'' Bactrospora inspersa''
*'' Bactrospora lamprospora''
*'' Bactrospora lecanorina''
*'' Bactrospora littoralis''
*'' Bactrospora medians''
*'' Bactrospora metabola''
*'' Bactrospora micareoides''
*'' Bactrospora ochracea''
*'' Bactrospora paludicola''
*'' Bactrospora perspiralis''
*'' Bactrospora subdryina''
*'' Bactrospora thyrsodes''
*'' Bactrospora totonacae''

References

{{Taxonbar, from=Q4840085

Arthoniomycetes
Arthoniomycetes genera
Lichen genera
Taxa described in 1852
Taxa named by Abramo Bartolommeo Massalongo