On Ceratolejeunea adantica, a new species of Lejeuneaceae (Jungermanniopsida) from Brazil

Ceratolejeunea atlantica, a new species of Lejeuneaceae collected in a remaining fragment of Brazilian Atlantic forest from Murici Ecological Station in Alagoas, Brazil, is described and illustrated. The main diagnostic characters of the species are bifid underleaves and perianths constantly with 4-bulbous horns. Additionally, it is recognized by lobules inflated throughout with a sharp and long apical tooth, presence of one utricle at the base of lateral branches, and geminate ocelli restricted to the leaf base. The new species is morphologically related to Ceratolejeunea malleigera (Spruce) Steph. and differences between the two species are presented. Ceratolejeunea malleigera and C. atlantica fit into subgenus Caduciloba except on account of the perianths with bulbous horns. The latter character, entire underleaves, and lobules inflated only near the keel without a prominent apical tooth, characterize the subgenus Ceratolejeunea. However, the discovery of this new species and C. malleigera raise questions on the use of differences involving perianth horns as a diagnostic feature for separating infragencric categories in Ceratolejeunea.