Phlyctis subargena
Phlyctis subargena is a species of crustose lichen in the family Phlyctidaceae. It forms thin, greenish-white patches on tree bark and reproduces both by powdery soredia and by small fruiting bodies that typically occur in clusters. The species is known only from montane forests in Gansu Province, north-central China.
Taxonomy
Phlyctis subargena was described as new to science in 2011 by Rui Ma and Hai-Ying Wang, based on bark-dwelling material collected in Gansu Province in north-central China. The holotype was collected at Qiujiaba at 2,450 m elevation on 2 August 2007 and is housed in the lichen herbarium of Shandong Normal University.The species was separated from other members of Phlyctis by a combination of abundant soredia, frequent clusters of small apothecia, and asci that usually contain two spores rather than one or eight; chemically, it contains the depsidone norstictic acid. It is most similar in appearance to the sorediate P. argena, but that species typically has solitary apothecia, one spore per ascus, larger spores, and a trace of connorstictic acid. Another sorediate relative, P. subuncinata, differs in having fusiform spores and different secondary metabolites.
Description
The thallus is crustose and thin, forming greenish-white patches on bark. Its surface is uneven and has a somewhat cobwebby or felty texture, and it often breaks into small, irregular about 0.1–0.2 mm across; a white may be visible at the margins and in cracks. The soralia are usually paler than the surrounding thallus and produce abundant powdery to granular ; neighbouring soralia may merge into diffuse, irregular patches.Apothecia are common and minute, usually occurring in clusters of 3–8 and partly immersed within sorediate thallus patches. The is reddish-brown, flat to slightly irregular, and usually dusted with white ; the is weakly developed. Microscopically, the spore-bearing asci are broadly club-shaped and two-spored. The colourless spores are, measuring 42–78 × 30–42 μm, and show no iodine reaction. The is a green alga with spherical cells 12–18 μm in diameter. In spot tests the is K+ and C−, while the medulla is K+, C−, and PD+. Thin-layer chromatography detected norstictic acid as the major lichen product.