Notes on the circumscription of the lichens Lecanora leprosa and L. sulphurescens (Lecanoraceae, lichenised Ascomycotina)

Lecanora leprosa and L. sulphurescens are two commonly misidentified pantropical lichens. A detailed circumscription is presented to help overcome such difficulties. Both species contain a chemosyndrome of chlorodepsidones based on gangaleoidin. The new depsidone chlorolecideoidin (methyl 2,4,9-trichloro-3,8-dihydroxy-1,6-dimethyl-11-oxo-11H-dibenzo[b,e][1,4]-dioxepin-7-carboxylate) has been shown to be a minor component of both species. Zusammenfassung. Lecanora leprosa und L. sulphurescens sind zwei häufig fehlbestimmte pantropische Flechten. Eine ausführliche Beschreibung der beiden Arten wird vorgelegt. Beide Arten enthalten ein auf Gangaleoidin basierendes Chemosyndrom von Chlordepsidonen. Das neue Depsidon Chlorlecideoidin (Methyl 2,4,9-Trichlor-3,8-dihydroxy-1,6-dimethyl-11-oxo-11Hdibenzo[b,e][1,4]-dioxepin-7-carboxylat) wird beschrieben. Es kommt in beiden Arten als Nebeninhaltsstoff vor. The tropical species of the Lecanora subfusca group are poorly known. While studying the Australasian members of this group, we soon realized that many specimens were misidentified with the collective names L. leprosa or L. sulphurescens. A number of these specimens, however, belong to different, similar species. Lecanora leprosa and L. sulphurescens are described here in some detail to clarify the circumscription of the species, including the secondary chemistry, which is an important character in the distinction of these taxa. Moreover, a new substance, chlorolecideoidin, was detected in most specimens of both species and is described here. Material and Methods Specimens were studied from the following herbaria: B, BRI, C, CBG, COLO, DNA, ESS, G, GZU, H, HO, LD, M, MEL, NSW, PC, PERTH, S, TNS, U, UPNG, UPS, WELT, ZT and the