Strigula

The genus was circumscribed in 1823 by the English mycologist Elias Magnus Fries. The taxonomy of the genus has undergone significant revisions based on multilocus phylogenetic analyses. Originally defined broadly to include species growing on various substrates, research revealed that foliicolous (leaf-dwelling) species formerly placed in Strigula actually form six well-defined clades that warranted recognition as separate genera. The foliicolous species have been reallocated into the following genera: • Strigula (sensu stricto) – Includes the type species S. smaragdula and is characterized by thickened, bright green to grey-green thalli with a Cephaleuros photobiont (algal partner), carbonized perithecial walls, small to medium-sized ascospores, and macroconidia with short to medium-sized appendages. • Serusiauxiella – A newly recognized genus with species that have a Trentepohlia photobiont and unique macroconidial appendages that rapidly grow to substantial lengths when observed in microscopic mounts. • Raciborskiella – Includes hypophyllous (growing on leaf undersides) species with very thin, bluish grey thalli, carbonized perithecial walls, large ascospores (30–70 μm), and terminal appendages on ascospores. • Puiggariella – Features species with distinctive thallus morphology displaying white papillae and non-carbonized (pale) perithecial walls. • Racoplaca – Comprises species with thin, finely lobed thalli of olive-brown to dark olive-green color which feature a characteristic thin black line along the lobe margins. • Phylloporis – Contains supracuticular species (growing on leaf surfaces) with a Phycopeltis photobiont, carbonized perithecial walls, and comparatively short asci and small ascospores. ==Description==

Strigula, in its currently defined narrower sense, is a genus of lichen-forming fungi characterized by its distinctive foliicolous (leaf-dwelling) growth pattern. These lichens form subcuticular thalli, meaning they grow beneath the cuticle of leaves, infiltrating between cell layers rather than simply growing on the surface. The thalli (lichen bodies) of Strigula are typically thickened, with a characteristic bright green to grey-green coloration. They form rounded patches with entire to margins on leaf surfaces. Strigula species develop a symbiotic relationship with a specific algal partner () in the genus Cephaleuros, which provides the lichen with carbohydrates through photosynthesis. Reproductive structures include perithecia (flask-shaped fruiting bodies) that are partially immersed in the thallus, appearing as small, basally immersed and apically erumpent black dots. The perithecial wall is , appearing jet-black in cross-section. The perithecia contain asci (spore-producing cells) that are (double-walled) with a short and narrow . Each ascus produces eight , which are arranged in one to two rows within the ascus. The ascospores are (spindle-shaped), single-septate (divided by one wall), colorless, and relatively small to medium-sized (7–25 × 4–6 μm). Strigula also produces asexual reproductive structures called pycnidia, which contain (larger asexual spores) with short to medium-sized gelatinous appendages that extend only slowly when observed in laboratory preparations. ==Species==

• Strigula acuticonidiarum – China • Strigula antillarum • Strigula bella • Strigula caerulensis – Australia • Strigula concreta • Strigula cylindrospora • Strigula depressa – Korea • Strigula fossulicola • Strigula fossulicoloides • Strigula guangdongensis – China • Strigula guangxiensis – China • Strigula indutula • Strigula intermedia – China • Strigula janeirensis • Strigula lacericola • Strigula laevis – China • Strigula lobulosa • Strigula macrocarpa • Strigula microcarpa – China • Strigula minor • Strigula minuta • Strigula multipunctata • Strigula nigrocarpa • Strigula nitidula • Strigula novae-zelandiae • Strigula obducta • Strigula oceanica • Strigula oleistrata • Strigula perparvula • Strigula platypoda • Strigula prasina • Strigula pseudoantillarum – China • Strigula pseudosubtilissima – China • Strigula pycnoradians – Thailand • Strigula pyrenuloides – Brazil • Strigula schizospora • Strigula sinoaustralis • Strigula sinoconcreta – China • Strigula smaragdula • Strigula stenoloba – China • Strigula subelegans • Strigula submuriformis • Strigula subtilissimoides – China • Strigula univelbiserialis • Strigula wandae ==References==