The lichen Leptogium subaridum, a new Mediterranean-NW American disjunction

Extract

Several epiphytic specimens of the genus Leptogium (Ach.) Gray with a foliose thallus and numerous marginal and laminal isidia collected in central and southern Spain, and previously identified as Leptogium magnussonii Degel. & P. M. Jørg., varied considerably. Two morphological forms have been differentiated: one with clusters of granulose or coralloid, aggregated isidia, identified as typical L. magnussonii and the other with clavate to dactyliform isidia as in L. subaridum P. M. Jørg. & Goward. Meanwhile, when studying the lichen L. lichenoides from some European herbaria, three epiphytic specimens belonging to L. subaridum, one from Morocco, one from Italy and the other from Greece, were identified. These new records of the latter species extend its distribution from NW America to S Europe and N Africa. In addition, mature apothecia are reported for the first time. We briefly characterize the species based on material from the new localities using the morphological and anatomical terminology proposed in Jørgensen (1994).