Indagine fitogeografica sulle felci delle grotte pugliesi

Abstract

PHYTOGEOGRAPHICAL RESEARCH ON THE APULIAN CAVE-DWELLING FERNS - Envoronmental gradients due to lighting and humidity are characteristic of the entrance of caves. These places are often suitable habitats for botanic species, mainly hygrophytes and heliophobe cryptogams, such as algae, mosses and ferns. This paper deals with the distribution of the species dwelling the Apulian caves, with particular reference to pteridophytes. Three different distribution types are identified: 1) some specie, e. g. Asplenium scolopendrium L. and Adiantum capillus-veneris L., behave like cave-dwellers; they area widely spread in the Apulian caves, also in accordance with large-scale phenomena, such as lithology. 2) Other species, e. g. Polystichum aculeatum (L.) Roth and Dryopteris affinis (Lowe) Fraser-Jenkins, are strangers over the Apulian land; they dwells the mountains of neighbour lands and, because their long-distance spores dispersal, they can reach the Apulian caves where they usually find an unsuitable habitat. 3) In one case, i. e. Asplenium marinum L., there are evidences of a ancient outcast species consequently climatic mutations.