Šilagėlės genties augalai yra nepaprastai gražūs, dekoratyvūs ir puošnūs, bet kai kurios šilagėlių rūšys sparčiai nyksta, todėl yra saugomos įvairių teisės aktų pagalba. Lietuvoje augančios pievinė (Pulsatilla pratensis) ir vėjalandė šilagėlės (P. patens) savo paplitimo arealuose yra nykstantys augalai. Vėjalandė šilagėlė dėl spartaus nykimo Europos mastu, visose šalyse kuriose ji paplitusi, yra įrašyta į saugomų rūšių sąrašus ir juose dažniausiai priskiriama prie išnykstančių ar pažeidžiamų rūšių kategorijų. Pievinė šilagėlė nėra taip sparčiai nykstantis augalas, todėl Europoje yra priskiriama endeminėms rūšims (PILT, KUKK, 2002). Siekiant parengti geras rekomendacijas šilagėlių apsaugai, kurios jas įgyvendinus duos teigiamus rezultatus, pirmiausia yra būtina surinkti visus įmanomus duomenis apie šią rūšį. / The genus Pulsatilla includes perennial plants of the Ranunculaceae family. In Lithuania this genus is represented by two species and one hybrid: P. patens, P. pratensis and P. ×wolfgangiana. P. patens is endangered throughout Europe and is included into the Red Data Books of almost all European countries. Endemic species of Europe P. pratensis is included into the Red Data book just in several European countries. P. ×wolfgangiana is very rare hybrid species, occurring in areas where both parental species occur together. The aim of this work was to estimate composition and state of populations of the genus Pulsatilla in Lithuania. The tasks of the work are as follows: 1) to reveal plant communities in which members the genus Pulsatilla grow; 2) to evaluate structure of populations according to stages of plant maturity; 3) to investigate density of P. patens and P. pratensis individuals in populations; 4) to compare variation of Pulsatilla morphological characters and their dependence on habitat conditions; 5) to evaluate optimum habitat conditions for Pulsatilla populations in Lithuania. Results of the research enable to reveal composition and state of populations of the genus Pulsatilla in Lithuania and to prepare recommendations for management of their habitats.

This thesis deals with interspecific hybridization in sympatric populations of Pulsatilla patens and P. pratensis. The key aim was to assess karyological and phenotypic variation in the study group. DNA flow cytometry revealed three non-overlapping groups of genome sizes, corresponding to P. patens, P. × hackelii and P. pratensis. The frequency of interspecific hybridization was low, accounting to approx. 3% of analyzed plants. Morphometric analyses identified a set a reliable species-specific characters, including number of divisions the leaf, length of petiole the part of leaf, number of smaller parts of leaf and colour of blossom. Although the majority of hybrid individuals flowered and set fruits, their fertility was reduced considerably. The threat from interspecific hybridization to parental species is therefore rather low.