Phyllopsora glaucella
Phyllopsora glaucella is a species of squamulose lichen in the family Ramalinaceae. The lichen forms mats of tiny green scales with small brown fruiting bodies and was first described from Mexican collections in 1926. It is distributed across tropical and subtropical America, ranging from Florida through the West Indies to Argentina.
Taxonomy
The lichen was first scientifically described by the Finnish lichenologist Edvard August Vainio in 1926, as a variety of the species Lecidea breviuscula. Lois Brako transferred the taxon to Phyllopsora in 1989. Einar Timdal promoted it to full species status in 2008. The holotype originates from Mirador, Veracruz, Mexico.Timdal separated P. glaucella from the P. corallina complex on both chemistry and morphology: the type contains the lichen substances vicanicin and norvicanicin, and it differs in squamule size, thickness, isidia form and attachment, and ascospore size. He found no trace of argopsin in the holotype and noted that a Peruvian specimen previously labeled as P. corallina var. ochroxantha in fact contains vicanicin and norvicanicin and belongs to P. glaucella.
Description
The thallus of P. glaucella forms an effuse mat of tiny green squamules up to about 0.5 mm wide. Squamules begin scattered and later become contiguous or overlapping; they are rounded to somewhat elongated, shallowly notched to incised, flat to slightly convex, and edged by a faintly hairy margin. A is well developed and reddish brown. Isidia are scattered to common, arise along squamule margins, and are typically long and simple. The outer "skin" is relatively thick and lacks crystals. The internal tissue of the lichen, the medulla, contains crystals that dissolve in potassium hydroxide solution and give negative standard spot test reactions.Fruiting bodies are common, small, and medium brown. They range from round and flat when young to irregular and strongly convex later; the margin is the same color or slightly paler and often finely hairy. Internal tissues are pale and lack crystals. Spores are narrowly ellipsoid, non-septate, and about 6.5–9 × about 2.5 μm. No pycnidia were observed in this species. The main substances are vicanicin and norvicanicin.