Bacidina pycnidiata is a species of crustose lichen in the family Ramalinaceae. It is widely distributed in Europe and North Asia. It is characterised by its whitish or cream-coloured pycnidia with long and ostiolar necks.
The lichen was originally placed in the genus Bacidia based largely on the characteristics of the apothecia. The authors noted, however, that some traits of the new species (e.g. a paraplectenchymatous outer exciple; narrow, needle-shaped ascospores; and threadlike conidia) suggested a placement in the segregate genus Bacidina. Due to uncertainties about the circumscription and nomenclature of that group, the authors instead included it in Bacidiasensu lato (in the broad sense). Molecular phylogenetic analysis showed that the lichen clearly belongs to Bacidina (related to B. inundata and B. caligans), and so a formal transfer to that genus was proposed by Czarnota and Beata Guzow-Krzemińska in 2018.[2]
Description
The crustose, greyish green thallus of Bacidina pycnidiata comprises tiny granules that are 20–30 μm in diameter. The granules are goniocysts, which are small, roundish aggregations of photobiont cells surrounded by fungal hyphae. The photobiont partner is chlorococcoid (i.e., green algae with a coccoid shape); their cells are either more or less spherical with a diameter of 7–13 μm, or ellipsoid, with dimensions of 8–12 by 5–8 μm.[1]
Bacidina pycnidiata produces pale apothecia that are 0.2–0.5 mm in diameter and up to 0.6 mm tall, and range in colour from whitish cream, to flesh-coloured, to pale brownish. Initially, they are constricted at the base with a slightly concave disc and a thick margin; this margin becomes thinner or even disappears in older individuals. The asci are of the Bacidia-type, with a cylindrical shape, a poorly developed or absent ocular chamber, and dimensions of 35–40 by 6–8 μm. Ascospores are needle-shaped (acicular) with three transverse septa, measuring 35–50 by 1–1.2 μm. The pycnidia have a whitish to cream colour (brownish in older specimens) and are more or less spherical with a diameter of 90–190 μm and an ostiolar neck measuring 120–200 μm.[1]
Bacidina pycnidiata is a pioneer species that grows over bryophytes, both terrestrial and epiphytic. Habitats include both old-growth and managed forests, and anthropogenic areas. Occasionally the lichen has been recorded on tree bark in shaded areas, or growing on other lichens,[3] as was the case with Caucasian specimens found growing on Nephroma parile.[4]
Originally described as having a distribution in mountainous areas of Central Europe, several records of Bacidina pycnidiata have been published that have expanded its known range considerably. It has been recorded from Belgium,[5] the Czech Republic,[6] Estonia,[7] Finland,[8] Lithuania,[9]Mordovia (Russia),[4] Poland,[10][11]North Caucasus,[12]Siberia,[3] and Ukraine.[13]
^Czarnota, Paweł; Guzow-Krzemińska, Beata (2018). "Bacidina mendax sp. nov., a new widespread species in Central Europe, together with a new combination within the genus Bacidina". The Lichenologist. 50 (1): 43–57. doi:10.1017/s0024282917000627. S2CID90382941.
^Ertz, D.; Diederich, P.; Brand, A.M.; van den Boom, P.; Sérusiaux, E. (2008). "New or interesting lichens and lichenicolous fungi from Belgium, Luxembourg and northern France. XI". Bulletin de la Société des naturalistes luxembourgeois. 109: 35–51.
^Vondrák, J.; Halda, J.P.; Malíèek, J.; Müller, A. (2010). "Lichens recorded during the Spring Bryo-lichenological Meeting in Chøiby Mts (Czech Republic), April 2010". Bryonora. 45: 36–42.
^Suija, A.; Leppik, E.; Randlane, T.; Thor, G. (2007). "New Estonian records: lichens and lichenicolous fungi". Folia Cryptogamica Estonica. 43: 73–76.
^Pykälä, J. (2008). "Additions to the lichen ora of Finland. III". Graphis Scripta. 20: 19–27.
^Motiejūnaitė, J.; von Brackel, W.; Stončius, D.; Preikša, Ž. (2011). "Contribution to the Lithuanian flora of lichens and allied fungi. III". Botanica Lithuanica. 17 (1): 39–47.
^Urbanavichus, G.P.; Urbanavichene, I.N. (2013). "Addition to the lichen flora of Russia. II. Bacidia pycnidiata". Novosti Sistematiki Nizshih Rastenii (in Russian). 47: 297–301. doi:10.31111/nsnr/2013.47.297.
^Dymytrova, L.V. (2013). "Lichens of the Lisnyky Botanical Preserve (Kyiv) and their indicator values". Ukrainian Botanical Journal. 70 (4): 522–534.