A taxonomic reassessment ofSpongites(Corallinaceae, Rhodophyta) based on studies of Kützing's original collections

Abstract

Results from critical studies of the original collections upon which Spongites Kutzing, 1841 is based have led to the designation of S. fruticulosa as lectotype species and to the resurrection and recognition of Spongites as a distinct genus of Corallinaceae (Rhodophyta). Spongites is characterized by the absence of geniculae, uniporate tetrasporangial conceptacles, a multistratose non-palisade and non-coaxial medulla (“hypothallium”) and cortex (“perithallium”), fusions between cells of adjacent filaments, and trichocytes which are solitary or arranged in a vertical series. Since at least 1883, the Kutzing epithet “fruticulosa” has been misapplied widely to a taxon with multiporate tetrasporangial conceptacles, whereas the type collection of S. fruticulosa possesses uniporate tetrasporangial conceptacles. Of the six original species, three (S. fruticulosa, S. racemosa, S. stalactitica) are retained in Spongites; S. dentata is referred to Lithophyllum and S. nodosa to Lithothamnion as distinct species; an...