Apospory in Mosses Discovered by Nathanael Pringsheim in a Brilliant Epoch of Botany

Abstract

The revolutionary advances in scientific botany in the mid- and last half of the nineteenth century included Nathanael Pringsheim's pivotal discovery of apospory in mosses: the regeneration of sporophytic tissue to form gametophytic structures, without the benefit of spores. This discovery was expanded later when the different chromosome numbers in the gametophytic (n) and sporophytic (2n) phases were revealed. Thus, the full significance of apospory was realized: the tissue regenerated by the sporophyte is gametophytic in morphology, but bears the chromosome content of the sporophytic tissue from which it arose. Pringsheim's discovery helped to promote the homologous theory of alternation of generations and, by clarifying the commonalities of the thallophytes, bryophytes, pteridophytes, conifers, and flowering plants, to suggest evolutionary paths for these groups. In this remarkable era, botanists turned with in