Studies on Colombian Cryptogams VII. Culture studies on the taxonomic relevance of costal anatomy in the Campylopus leucognodes-subconcolor complex and in Campylopus pittieri

Observations on costal anatomy in Colombian material of the Campylopus leucognodessubconcolor complex revealed a correlation between habitat humidity and degree of cell wall thickness. Cultivation experiments confirmed the assumption that the presence or absence of pseudostereids in this group is environmentally controlled. The taxonomic consequence of these findings makes us consider C. leucognodes (C. Müll.) Par. and C. argyrocaulon (C. Müll.) Mitt. synonymous with C. subconcolor (Hampe) Mitt.; the latter name is correct for the species in its new circumscription. Cultivation experiments on Campylopus pittieri Williams produced no effect on the observed variation in the costal cell-pattern, but cultivation seemed to suppress the development of apical ridges on the dorsal surface of the costa. The taxonomic value of the two varieties of C. pittieri is discussed.