22 - Studia Geobotanica. An international journal - Vol. 22 (2003)

A qualitative and quantitative analysis of airborne pollen collected with a Cour trap in Trieste (NE Italy) is presented. The behaviour of 30 pollen types, corresponding to 81.4% of the total collected pollen, was studied. Average results for the period 1987-1996 are presented, together with the highest values found. The highest mean weekly concentrations of total collected pollen are recorded from middle February to middle July, when approximately 86% of the annual total pollen was collected. During the year several peaks occur, principally due to Cupressaceae in early March, and to Quercus, Ostrya, Moraceae, Urticaceae, Pinus and Grarnineae in May. The variation in the annual total concentration over the years shows extraordinary concentrations of Abies, Picea, Fagus and Olea pollen in 1992. Most pollen types are from woody species (56.6%), while a minor contribution comes from herbaceous species (24.8%). The mean composition of the atmospheric pollen spectrum of Trieste reflects well the natural woodlands surrounding the town, and its ornamental and ruderal floras.

A karyological analysis of some taxa of Genista sect. Spartioides, distributed in the Western part of the Mediterranean region, was carried out. In the Genista cinerea group, G. majorica and G. cinerea ssp. cinerea have the chromosome number 2n = 48+(0-2B), while a population of G. cinerascens from Portugal has the new numbers with higher degrees of ploidy 2n = 72+(0-SB), rarely 2n = 96+(0-2B). G.florida s.l., like ssp. florida and ssp. polygaliphylla, have 2n = 48+(0-3B), while ssp. maroccana 2n = 46+(0-2B). A new number 2n = 72, with a different grade of ploidy, was counted for G. obtusiramea. In several populations of G. pilosa the euploid number 2n = 24+(0-3B) was found; only in one population from Val D'Aosta the aneuploid numbers 2n = (40, 42), 44+(0-JB) were counted. A comparison was also made with karyological data already available for ali the Western taxa of sect. Spartioides and for G. pilosa.

57 lichen species are reported from the Terra Nova Bay area (Northern Victoria Land, continental Antarctica), on the basis of collections from the Italian Antarctic Expeditions 1987-1996. 51 of them were identified to species level. A key for their identification is provided. Morpho-anatomical descriptions and nomenclatural, taxonomic and phytogeographical remarks are given for each taxon. Blastenia viridans Js. Murray is reduced to synonymy with Caloplaca athallina Darb.