Pre-Linnaean herbaria have a growing value for botanists and historians of science. A unique example is a four volume herbarium from the early 18th century preserved in the archives of the Herbarium of the Faculty of Biology, University of Warsaw. They consist of one, originally five volume set. We proved that the plants had been gathered by the famous naturalist Georg Andreas Helwing (1666-1748), and his son-in-law, Matthias Ernst Boretius (1694-1738), and they annotated and classified the exhibits. Boretius was born in Prussia, in Lec (now: Giżycko). He acquired his academic training in Königsberg and Leiden, and deepened it by scientific travels. He was the first in Masuria to promote vaccination against smallpox. Earning the reputation of a distinguished scholar, he was appointed Royal Physician and Crown Councilor of the Prussian court. He died in 1738 at the age of just 44, leaving the herbarium vivum – a magnificent remnant of his times. There are over 900 cards with glued specimen, signed in three languages: Latin, German and Polish. It includes vascular plants, liverworts, true mosses, clubmosses, algae and macrofungi. Boretius implemented the system made known by the French botanist Joseph Pitton de Tournefort (1656-1708). His system divided the plant world into 22 classes, based on flower morphology but also retaining the traditional split into trees, shrubs and forbs. The choice of this arrangement by Boretius was an innovation; the earlier plant collections of his tutor Helwing lacked any attempt to classify plant species.
Among the 2750 species of the Polish vascular flora, about 500 species are threatened with extinction and 430 of them are strictly protected by national law. The FlorNatur project for the ex situ conservation of the most endangered species was started in 2009. The aim of the project is to collect seeds of 61 species from 161 sites in eastern Poland and store them in the Seed Bank of the Polish Academy of Sciences Botanical Garden - Center for Biological Diversity Conservation in Warsaw- Powsin. A complementary program is being carried out by the Forestry Gene Bank at Kostrzyca in western Poland. Their task is to collect 58 species from 129 natural sites in the western part of Poland. To date, seeds of 31 species from 56 populations have been collected, tested and stored in liquid nitrogen.