Department of Botany,
Bharathiar University, Coimbatore - 641 046
Physcia tribacia (Ach.) Nyl.
Family :
Physciaceae
Nylander, Flora 57: 307: 1874
Basionym: Lecanora tribacia Acharius, Lich. Univ.: 415. 1810
ID :
BU/BRL/2022/033
Thallus :
Foliose, orbicular to irregular, up to 3 cm diam.
Lobes :
Up to 1 mm wide, sometimes scale-like; margin: mostly crenulate when soralia not present, eciliate
Upper Side:
Whitish gray to dark gray or cream-colored (with darker margins), shiny and epruinose or rarely weakly pruinose, sorediate
Isidia :
In marginal or terminal soralia that develop from the lower surface of the lobe tips, eroding the tip and sometimes also the lower surface
Lower Side :
White to brownish gray, often weakly rose colored
Medulla :
Upper cortex: paraplectenchymatous with rounded cells, medulla: white, lower cortex: paraplectenchymatous with rounded cells
Uncommon, up to 2 mm diam.; margins: partly sorediate; disc: dark brown to black, without pruina
Apothecia :
Brown, 1-septate, intermediate between Physcia- and Pachysporaria-types, (16-) 17.5-21.5 (-22.5) x (7.5-) 8.5-10.5 (-12) µm Pycnidia: usually numerous conidia: subcylindrical, 4-6 x 1 µm
Ascospores :
Cortex K+ yellow, C-, KC-, P+ yellow; medulla K-, C-, KC-, P- Secondary metabolite: upper cortex with atranorin
Chemistry :
