Botanica Lithuanica , Volume 6, Number 4

2000 m.

This paper continues publication of the conspectus of alien plant species recorded in Lithuania. The Rosaceae family in Lithuania contains 43 alien plant species. Data on the first record, distribution, habitats, level of naturalization means, of immigration, and biology (time of flowering and fructification, data on reproduction) of each species are presented. 31 here described alien species are naturalized and 11 are casuals. Distribution of seven species is mapped. One species (Crataegus monogna) is excluded from the list of alien plant species.

Keywords: alien plant species, conspectus, Rosaceae distribution, naturalization, reproduction, Lithuania.

Habitats of Rubus plicatus Weihe et Nees were investigated in the forest of Kintai (Šilutė district, West Lithuania) in 1998–1999. The aim of this research was to characterise morphological variation of R. plicatus in the habitats of three different types. Illumination of the habitats was the principal ecological factor, which caused the morphological variation of R. plicatus. The plants tended to be higher and produced more fruiting shoots in the habitats with better illumination. Plant height and density of shoots in the habitats appeared to be positively correlated.

Keywords: Rubus plicatus, habitat, morphology, variation, ecological conditions, Lithuania.

Investigations on genetic variation, geographic and hierarchic distribution of Quercus robur L. and Q. petraea (Matt.) Liebl. are indispensable conditions for the rearrangement of Lithuanian genetic resources conservation system. The occurrence area, spreading nature, and introgression zone of Q. petraae are still not known. Under the processes of global climate warming the conditions for sessile oak, as for the species of warmer climate comparing to Q. robur, would become more favorable in Lithuania. Trakas forest has the status of the Strict Nature Reserve in Meteliai Regional park (southern Lithuania) and is famous because of abundant presence of sessile oak, which has natural limit stretching farther south. The forest was investigated for the composition of oak species and possible interspecific hybrids by the aid of 11 morphological traits of fallen leaves. Trees possessing features of hybrids comprised up to 38%, while Q. petraea only 18 % of the total number of trees. The relief and soil types in the area are very altering and could be considered incentive for the processes of hybridisation. The diversity of the classified tree forms indicates that these hybridisation processes have a long history in Trakas forest.

Keywords: Quercus robur, Quercus petraea, discrimination of species, infraspecific hybrids, morphological traits of leaves.

The paper presents the data on the distribution of plant communities in an island of the Neris river. The dependence of the distribution of plant communities on ecological conditions and location in the island is discussed.

Keywords: Neris river, islets, plant communities.

Five communities of macroalgae occurring along the Lithuanian coast of the Baltic Sea are described. The largest areas are covered by the communities of filamentous green algae dominated by Cladophora glomerata. They develop in shallow (0–3 m depth) waters. Red algae communities, dominated by perennial Furcellaria lumbricalis, occur in deeper (4–12 m depth) areas. The rare community of Fucus vesiculosus is described from only one locality; therefore, the data about its distribution is incomplete. Habitat of a rare and endangered species Zostera marina near Palanga is also described.

Keywords: benthic macroalgae, phytobenthos, communities, Baltic Sea, Lithuania.

oday in Lithuania alien woody plants belonging to more than 3000 taxa are cultivated. They were introduced into Lithuania during the period of a few centuries. Most foreign plans have arrived into Lithuania through Western Europe, thus the regularities of the introduction of alien plants into Lithuania in the 14th–20th centuries are similar to the process of introduction in Western Europe. However, the time of introduction of certain plants, their quantity and the course of some periods are slightly different. Alien woody plants were introduced into Lithuania later than in Western Europe. In the 20th century the introduction of woody plants into Lithuania has been influenced by Russia, but recently the process becomes similar to the introduction in Western Europe again.

Keywords: woody plants, introduction, history 14th–20th centuries, regularities, botanical gardens, Lithuania.

The growth of fruit bodies of chanterelle was investigated in study plots (forest of the Cladonio-Pinetum sylvestris association) in south-west Lithuania. Signification differences in the rate of growth of investigated fruit bodies might be partly explained by their location. The changes of minimal day air temperature during the investigation period had some influence on the changes of growth rate. Other compared environmental factors such as maximal day air temperature, minimal and maximal day air humidity, and rain fall were insignificant. One of the most important environmental factor was soil humidity.

Keywords: Cantharellus cibarius, growth rate, environmental factors, Lithuania.