17 - Studia Geobotanica. An international journal - Vol. 17 (1999)

The distribution of epiphytic lichens on Quercus pubescens on the Adriatic side of Central Italy (Abruzzo) was studied along an altitudinal gradient from O to 1000 m by multivariate techniques. The general response of epiphytic lichens to elevation was similar to that found on the Tyrrhenian side of Italy, with great differences in community structure and the altitude of 500 m as an ecotone. However, suboceanic species, which are widespread on the Tyrrhenian side, were rare and confined to higher elevations, or not present at all in the Adriatic gradient. The use of epiphytic lichens as phytoclimatic indicators is discussed.

A karyological analysis of two species endemic to Northwestern Africa (Genista ifniensis A. Caballero and G. tricuspidata Desf.) showed that both species have the chromosome number 2n = 48. A comparison was also made with karyological data already available for the other taxa of sects. Scorpioides Spach and Voglera (Gaertn., Mey. & Schreb.) Spach.

NOTES ON THE URBAN FLORA OF TRIESTE cNE ITALY). Some new contributions to the knowledge of the urban flora of Trieste are given. Among the annotated species, Atriplex micrantha is reported as new to Italy, Lepidium latifolium subsp. latifolium, Lathyrus ochrus, Teline monspessulana and Eleusine tristachya are new to the flora of Friuli-Venezia Giulia (North-eastern ltaly).

THE VEGETATION OF THE SEDIMENTARY COAST OF FRIULI-VENEZIA GIULIA (NE-lTALY) WITH PARTICULAR REFERENCE TO THE NORTHERN ADRIATIC REGION. This paper is devoted to the study of the psammophilous and halophilous vegetation of the Northern Adriatic Sea (from Sefovlje, Republic of Slovenia, to the mouth of the Po river) and particularly to the definition of a phytosociological scheme for the vegetation of the sedimentary coast of Friuli-Venezia Giulia. Due to its alluvial origin, the study area is geomorphologically homogeneous, being constituted by lagoons bordered by sandy shorelines, and in the Mediterranean basin it is distinctive because of a strong Eurosiberian climatic influence, high tides and wet salted soils. About 900 relevés taken from the literature and 65 unpublished relevés from Friuli-Venezia Giulia were considered. The multivariate analysis of the relevés allowed to reassess the syntaxonomical position of several associations, placed by some Authors into other classes of vegetation. Some problems arised with the halophilous vegetation, as some species, although characteristic of their classes, are present with high frequencies also in other classes. Furthermore, the boundaries between classes are rather vague if only the floristic composition is considered. However, this problem can be overcome by taking into account also structural data (life form and growth form). These syntaxonomical difficulties reflect the peculiar character of a vegetation which seems monotonous, but is on the contrary very heterogeneous, being constituted by a fine scale mosaic. The vegetation of the study area is more similar to that of the western than to that of the Eastern Mediterranean coast, and. has a strong affinity with the vegetation of Atlantic Europe.