, Volume 3, Issue 1-2, pp 1-123

Ricerche sulla flora briologica xerotermica delle Alpi Italiane

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Summary

A methodic study of the penetration of thermophilous — chiefly xerothermophilous — Bryophyta in Southern Alpine valleys, has been made, examining very many sectors of the Italian Alps, from Monfalcone to Susa. This work has been executed chiefly on personal collections made on hundreds of stations, but also on the data published on this subject. The penetration of xerothermic Bryophyta is evident from the analysis of 436 surveys made on the stations progressively along the single ways of alpine valleys.

A number of associations is described or more exactly defined; the uniting into alliances, in some cases, has been attempted, on the base of natural relations as visualized in the field. The best defined are:

  • All. Abietinellion

  • Ass. Abietinelleto-Pleurochaetetum

  • Ass. Abietinelletum

  • All. Grimmion commutatae

  • Ass. Grimmietum commutatae

  • All. Crossidion

  • Ass. Crossidietum

  • Ass. (Subass.?) Grimmietum tergestinae Very many subassociations and facies are described.

  • The origin and composition of the southern-alpine, xerothermic bryological flora have been investigated and are expressed in the following scheme.

    1. —In a “continental steppic” group are united:

    2. “continental” species s.l. (Abietinella-Type) with a large area, and very eurythermic.

    3. “continental boreo-meridional” species (Pottia Heimii Type) with a large area, but with more evidently meridional affinities and sometimes with austral disjunctions. Probably boreal-tertiary.

    4. “continental-bizonal” species (Mannia fragrans Type), rather largely distributed, with peculiar disjunctions in altitude, sometimes with differentiated races of recent origin.

    5. “continental meridional” species (Aloina ericaefolia Type, Cinclidotus Type) very similar to type (c), but more largely distributed in the mediterranean region.

    6. “hyperxerophytic aralo-caspian” species (Tortula revolvens Type), xeromorphic, evidently derived from species with wide holarctic or mediterranean distribution.

    presentato alla redazione il 16-V-1950.