10 - Studia Geobotanica. An international journal - Vol. 10 (1990)

SECOND CONTRIBUTTON TO THE KNOWLEDGE OF MYXOMYCETES IN THE TRIESTE KARST. 34 species of Myxomycetes are reported from the Trieste Karst (Northeastern Italy ), 25 are new to the survey area, 11 are new to Italy.

The transported and deposited pollen curves of 12 tree taxa in the outskirts of Trieste are reported. Meteorological data, the frequency of the taxa in the survey area, and phenologic observations on the anthesic periods have been used for the interpretation of the pollen curves. There is a generally good correspondence between pollination and deposition peaks, and the anthesic periods. The pollination curves allow to distinguish the contributions of sources at different distances from the trap. There are some correlations between meteorological factors and quantitative variation of airborne pollen.

This paper discusses the geographic trends in the distribution of the Pontic phytogeographical element (including Pontic-Mediterranean species) from the northern Adriatic coasts (Trieste Karst region) to the South-East Alps and pre-Alps. The number of Pontic species decreases slightly from the Karst towards the pre-Alps, with a sensible reduction from the pre-Alps towards the centre of the Alpine chain. This pattern can be related to temperature. The geographic variation of life forms shows a simplification of the life form spectrum: the geophytes, being less dependent on environmental conditions, are the life form with the lowest geographic variation.

This paper deals with the distribution, ecology and phytosociology of Moehringia tommasinii March., a stenoendemic species that occurs at the border between Italy and Yugoslavia, near Trieste. A new phytocoenosis of the submediterranean limestone rocks in the North-Adriatic area is described: Asplenio-Moehringietum tommasinii (Centaureo-Campanulion), which is characterized by Asplenium lepidum and Moehringia tommasinii.