Parmelia pseudoshinanoana

Parmelia pseudoshinanoana is a species of corticolous (bark-dwelling) foliose lichen in the family Parmeliaceae.^[2] Described from Mount Fuji in 1951, this lichen is widespread across Japan, occurring on tree bark in temperate forests throughout Honshu and Shikoku. The species forms pale greenish- to brownish-grey rosette-shaped growths 6–12 cm across and is distinguished by its lobe edges that become densely covered with tiny upright projections and a continuous white rim of small pores—features that help separate it from the related P. shinanoana, which has simpler root-like structures and different chemistry.

Parmelia pseudoshinanoana was described by Yasuhiko Asahina in 1951 from the Omiya-guchi, 2-gōme route on Mount Fuji (Suruga Province).^[3] In his 1987 Parmelia monograph, Mason Hale placed Parmelia laevior f. microphyllina Hue (1899; Japan^[4]) in synonymy with this species. Asahina regarded P. pseudoshinanoana as a lobulate relative of P. shinanoana; both have a continuous, pale marginal band of pseudocyphellae, but P. shinanoana typically has mostly simple (unbranched) rhizines and a different chemistry (gyrophoric acid in the cortex).^[5]

Parmelia pseudoshinanoana is a foliose lichen that forms fragile, pale greenish- to brownish-grey rosettes 6–12 cm across. Its lobes are more or less linear and contiguous, 1.5–3 mm wide; their margins become densely covered with tiny, slightly erect lobules (0.2–0.3 mm wide, 1–2 mm long). The upper surface is flat and shiny, often faintly white-pruinose at the tips, and shows a more-or-less continuous white rim along the edges formed by marginal pseudocyphellae (small pale pores). The lower surface is black and densely rhizinate; the rhizines are shiny and become densely squarrosely branched, 1–3 mm long. Pycnidia have not been observed. Apothecia are infrequent, short-stalked to nearly sessile, 2–4 mm in diameter, with a finely scalloped, pseudocyphellate thalline rim. The spore-bearing tissue (the hymenium) is 55–60 μm tall and the ascospores measure 6 × 10–12 μm with an epispore about 1 μm thick. The lichen contains atranorin and salazinic acid.^[5]

The species is widespread but not abundant in Japan, growing on the bark of trees in temperate forests. It has been recorded from numerous prefectures across Honshu and Shikoku.^[5]