There are three main ways to divide the Earth’s terrestrial biota: 1) the traditional division into realms justified especially in the tropics and the Southern Hemisphere; the author has proposed to define a realm as an area over 106 km2 and rich in endemic families; 2) latitudinal zonation most feasible on the lowlands of the Nothern Hemisphere; and 3) the division into biomes as a rough generalization embracing zonal and mountain ecosystems for all continents; the author has proposed a division into 12 main biome types.

Keywords: biogeography, biomes, endemic families, realms, zones.

Genus Potentilla L. (Rosaceae) is represented by 24 species in the three Baltic countries. Seven of them are rare adventives, nine native species grow on the borders of their areals and only eight taxa lie in the central part of their distribution area here. Differences in distribution of the genus Potentilla among the three Baltic countries is analysed and problems connected with their synonyms and nomenclature are discussed.

Keywords: Potentilla, distribution, nomenclature, Estonia, Latvia, Lithuania.

Discussion on the status of Colchicum autumnale and Astragalus cicer in Lithuania and neighbouring countries is presented. It is concluded that Colchicum autumnale is some localities in Lithuania is an accidental immigrant and in others is a cultivated plant run wild. Most probably, in neighbouring regions (the Baltic countries, the Kaliningrad region, Belarus, the Leningrad region) this species has the same origin. Astragalus cicer is supposed to be doubtfully native in two localities in the southern part of Lithuania, whereas in all other known localities it is a naturalized immigrand.

Keywords: Astragalus cicer, Colchicum autumnale, status, native, immigrant, Lithuania, Baltic region.

While investigating willow species distribution in Lithuania, it was established thet the western areal border of Salix lapponum and S. myrtilloides crosses southeaster Lithuania. These species are most frequent in Caricetum limosum, Caricetum lasiocarpae, and Caricetum diandrae communities. The eastern border of S. repens areal crosses western Lithuania. Two species of the sect. Daphnella grow beyond the borders of their continuous areal: S. acutifolia in southeastern Lithuania and S. daphnoides in western Lithuania. Three species widespread in Lithuania – S. alba, S. purpurea and S. viminalis – are growing on the edges of their areals.

Keywords: Salix, distribution, areal, Lithuania.

Carex brizoides L. is a rare species in Lithuania, where it occurs in the western part. It grows in thin, deciduous forests on lakesites that flood in the spring; in sparse growths of trees in wet, mixed forests; at drainage ditches of humid deciduous – and, rarely, coniferous – forests ; in thinned young, growth; and by roudsites. C. brizoides is found in Lithuania in Tilio-Carpinetum betuli association communities.

C. globuralis L. is a rather rare species, although it is widespread throughout Lithuanian. It is found in wet fir-groves, birch groves, marshy pine, bilbery-spruce, bilbery-pine, anr sometimes in boggy, mixed forests, as well as in wood-cutting areas, shrubberies and bogs. In Lithuania as well as in northeastern Poland C. globularis is characteristic of Molinio-Pinetum sylvestris (J. Mat. 1973) Mat. 1984 association communities.

Keywords: Carex brizoides, Carex globularis, distribution, Lithuania.

After examining numerous specimens from various parts of Lithuania it was ascertained that all earlier data on Eurhynchium striatum, as a species common in Lithuania, in fact dealt with E. angustirete instead. E. striatum seems to be a rather rare species distributed mainly in suboceanic parts of Lithuania.

Keywords: mosses, Eurhynchium striatum, E. angustirete, distribution, plant communities, Lithuania.

This paper will report the results of research conducted from 1991 to 1994 on the Lithuanian seacoast dunes, concerning the effects of recreation on Lathyrus maritimus. This plant is not only a decorative plant: its long rhizome laso serves the important function of strengthening the dunes. Unfortunately it is very sensitive to trampling and has vanished from those parts af the dunes with the greatest tourist traffic. Lathyrus maritimus grows throughout the seacoast dunes, particularly in the communities of Leymo-Ammophiletum oriento-balticum. On the dunes of the midland seacoast and in their environs the densiy of Lathyrus maritimus plants in 1994 was 0.3 thousand specimens/ha. In territories more remote from the beach the density of the plants fluctuates around 2.0 thousand specimen/ha. At the same time, the populations of Lathyrus maritimus on the Kuršių spit dunes are 2.5 times denser than thoseon the midland seacoast. The highest density of the seashore plants was observed in those seacoast relief elemenst where the average grass vegetation projection covering fluctuates between 50 % and 70 %. From 1991 to 1994 the number of Lathyrus maritimus plants on the seacoast dunes had decreased: 10 % on the Kuršių spit dunes, and 24 % on midland dunes.

Keywords: Lathyrus maritimus, polulation, dynamics, recreation, Lithuania.

Lithuania’s critical position from the geobotanical point of view determines certain species composition and abundance of indigenous plants. The temperate submeridianal species reach the northern border of their distribution areas. Some of them have important economic properties while the natural resources are of insignifical value. The main factor limiting the distribution and abundance of these plants is ecological conditions. Distribution of Arnica montana, Centaurium erythraea, Plantago arenaria and Lotus uliginosum is very limited with respect to their habitats and territory within the country, while the ecological distribution of Betonica officinalis and Sanguisorba officinalis is wider. Most populations of these species do not have any economical value, although they are important as genetic resourses. The protection and increase of indigenous useful plant species should be carried out during their cultivation.

Keywords: Arnica montana, Centautium erythraea, Plantago arenaria, Lotus uliginosum, distribution, useful plants, Lithuania.

Specific traits are observed in wild berry plants in connection with their distribution, i.e. those occurring on the border of their distribution area. The paper includes two parts: a case study of Rubus chamaemorus and a study of the intraspecific Vaccinium taxa. Rubus chamaemorus, a plant with a northern distribution area, has a low fruiting capacity in Lithuania for reasons that have not been identified completely. During the most recent years of investigation, a decrease in cloudberry sites was observed. The reduced number of unspoiled oligotrophic bogs as a consequence of land reclamation and peat harvesting is tha most likely explanation for this.

A rather large number of intraspecific Vaccinium taxa indicates a high diversity of Vaccinium species in the area investigation. The reasons for this are not clear. Nevertheless, the areas containing the rare taxonomic units of useful plants should be legally protected to ensure their conservation and availability for scientific use.

Keywords: distribution, intraspecific diversity, Rubus chamaemorus, Vaccinium, Lithuania.

Some stages of the compilation of a Red Data Book of the Communities of Lithuania are discussed and a list of plant communities proposed to include in the book are presented. Among the 54 Lithuanian communities requiring protection most communities are spread in water bodies and in coastal zones.

Keywords: plant communities, protected communities, list, Lithuania.

Three closed municipal waste dumps in Vilnius were investigated. In terms of botanical diversity, the Belmontas waste dump was the most interesting for its spontaneous wood vegetation. According to official data this waste dump functioned from 1969 to 1979. The difference in altitude between the waste dump and its environs (the valley of Vilnia river) is 20 m. The Belmontas waste dump is surrounded by very steep, almost vertical slopes. Here wood vegetation grows spontaneously and undisturbed. Ecological diversity was estimated in four plant communities by V. I. Vasilevič’s method and variuos indices of species diversity were used.

Keywords: vegetation, community, ecology, waste dump, Vilnius, Lithuania.

Grey alder (Alnus incana L.) is widely distributed in Lithuania. Yhe agricultural area north of Kaunas is rich in grey alder and it is an essential aspect of the landscape both sceniccaly and ecologically. Damaging to the agricultural landscape, it forms the worst aspect of a fast-movimg process of visual changes, particularly in wet and fertile soils. It is necessary to take permanent actions against the gray alder’s aggressiveness.

Keywords: Alnus incana, range, distribution, scenery, landscape, Lithuania.

The object of the studies conducted in the years 1987-1991 was the isolated population of Senecio rivularis in Roztocze National Park, southeastern Poland, i.e. at the northeastern border of the species’ geographical distribution. Studies aimed to learn about the probability and rate of attaining succesive developmental stadia of individuals in different parts of the population areal, and how the development rate of individuals affects the increasing of population abundance, density and spatial structure.

Keywords: Senecio rivularis, demography, isolated population, Poland.

A comparative analysis was made of eight elementary floras situated along the boundary of the Central and Eastern European floristic provinces in the Volyno-Podolian elevation. Based on a comparative analysis of the special species’ complexes and on peculiarities of the abiotic lanscape components, geomorphological factors were found to be significant in determining the present diversity level of the marginal floras of this type. The relative continuance of the phytochorias leads to a gradual modification of the species’ composition and the structure of the floras. The high sensitivity of these floras makes it especially important to reserve territories for the conservation of large regions of landscape diversity.

Keywords: Marginal flora, Western Ukraine, comparative analysis.

The results of the chorological investigation on the genus Alchemilla L. (34 species were found in the regional flora) make it possible to distinguish chorological groups according to definite subdivisions of the floristic districts. The results confirm a concordance of the agamospecies taxa with general florochorogical regularities characteristic of sexually reproducing plants.

Keywords: Alchemilla, chorology, western Ukraine.

Seventy-five species of the Carex L. genus were found in the flora of Ukrainian Carpathians during an inventory and critical-taxonomical study. It was determined that 24 species (32 %) among them are rare in this region.Among rare species of the genus Carex in the Ukrainian Carpathians, 21 have disjunctive distribution areas and three are on the edge of their ranges.

Keywords: Carex, distribution, rare species, Eastern Carpahtians, Ukraine.

Some corrections to the preliminary list of strictly dioecious angiosperms in Estonia (Reier, 1991) are made. Potentilla fruticosa is added. The status of Honckenya peploides, Serratula tinctoria, Myrica gale and Empetrum nigrum in Estonia is unclear and needs further investigation.

Keywords: angiosperms, dioecious, gymnodioiceous, Potentilla fruticosa, Estonia.

Lactuca tatarica in the Baltic region is an immigrant plant, originating from the steppe zone. It has naturalized in coastal zones and is spreading intensively. In cool and humid climate it can spread only vegetatively.

Keywords: Lactuca tatarica, Baltic Sea, coastal zone, colonization, Botrytis cinerea.

Distribution of Cerastium sylvaticum in southwestern Lithuania is described. All recently know localities of this species are compactly concentrated in this part of Lithuania. Characteristics of habitats of C. sylvaticum are presented. It is supposed that this species widespread in southwestern Lithuania but probably often is not distinguished from Cerastium holosteoides Fr.

Keywords: Cerastium sylvaticum, distribution, Lithuania.

The distribution and preferences for ecological conditions of two rare species in Estonia Cephalanthera longifolia and C. rubra are described. Recruitment is predominantly vegetative. Dormancy lasting for one or two years is reported in both species.

Keywords: Cephalanthera longifolia, C. rubra, habitat, clonal growth, genet size, dormancy.

The adaptation of Beckmannia eruciformis in cultural meadow communities is analysed. According to the research results, Beckmannia eruciformis in the grass mixtures is desistant. Optimal conditions for growing the species is 1-15 cm of groundwater. Beckmannia eruciformis, in such conditions, supresses other species and predominates in the grass composition from the fourth to the twentient year of the meadow’s development.

Keywords: Beckmannia eruciformis, adaptation, cultural meadows, Lithuania.

The genus Betula is represented by four species in Lithuania. Two of them form forest communities. Only some birch grove communities are primary forests, while most are secondary. The analysis of birch groves indicated that Betula pubescens predominates in primary birch grove communities, while Betula pendula forms secondary communities. In the class Alnetea glutinosae Br.-Bl. et R. Tx. 1943 the sub-association Carici elongatae-Alnetum betuletosum pubescentis Bodeaux 1955 is singled out.

Keywords: Betula pendula, Betula pubescens, communities, primary forest, secondary forest, Lithuania.

Ecological characteristics of species of Oak-hornbeam communities described by P. Snarskis were analysed.

Keywords: area, oak-hornbeam forest, ecology, Lithuania.

Fodder galega (Galega orienalis Lam.) is an important leguminous fodder crop because it has a high productivity and nutritive value, can grow from 7 to 15 and more years in the same place, and increases soil fertility. The present research treats the dependence of green matter yield on sowing time, and the effect of seeding rate and row spacing on the productivity and nutritive value of galega.

Keywords: Galega orientalis, fodder plan, cultivation, Lithuania.

The present research aimed to determine dose-response relationships of SO2 + NO2 for Briza media and Agrostis tenuis. The data obtained were interpreted by analysis of variance techniques.

Keywords: SO2, NO2 acidic pollutants, dose-response, photosynthesis, growth analysis, Briza media, Agrostis tenuis.