The extent of devastation revealed on the morning of March 2, 1943 was described by Pilger (1953a: 4). The eastern part of the Botanical Museum housing the library and the bulk of the herbarium had been burnt out, as well as the workrooms in the central part of the building. Only those collections that had been kept in the basement and in the west wing of the Museum were saved.
Since it was not possible to store the collections that survived in the less damaged parts of the building this material was evacuated eventually to seven different locations (Pilger 1953a: 18 f.). The most important collections - the Herbarium Willdenow, the ca. 20,000 types of Phanerogams that were saved, duplicates of valuable collections etc. - were stored in a mine at Bleicherode in Thuringia. Also kept at the same place were the very large collections that had been handed over to the Berlin Museum in 1944 from the Zoologisch-Botanische Gesellschaft in Vienna and the Botanical Institute of the University of Vienna, namely large parts of the broken up herbarium of the Zoologisch-Botanische Gesellschaft (cf. Lack 1980), Herbarium Ullepitsch (Lack & Wagner 1985), Herbarium Reuss and other collections.
The fate of each of the evacuated collections was different: The Hieracium collections moved to Eberswalde and the Lichen herbarium of J. Hillmann stored in the church of Buckow were destroyed by fire. The large herbarium of the Naturhistorischer Verein für die Preussischen Rheinlande und Westfalen evacuated to the Erwin Baur Institute at Müncheberg was removed by the Soviet authorities to an unknown destination and, in 1964, presented to the Humboldt University in East Berlin. In 1993 this collection came back to B when the BHU herbarium was incorporated.
The extraordinarily valuable collections at Bleicherode, which were also missing since March 1946, turned up again in the former Staatsbibliothek in the Soviet sector of Berlin at the end of 1947. Because the Botanical Museum was located in the American sector it was separated in March 1946 from the University, the center of which was in the Soviet sector. Because of this situation the authorities of the University did not want to return the collections to the Botanical Museum. After some difficult negotiations the material came back in March 1948 in exchange for the library of the Institute of Physics of the Berlin University which had been evacuated to Dahlem during the war. The entire collection of Pteridophytes came back even later.
The Director of the Museum at that time was R. Pilger, successor to Diels who had died in November 1945. Pilger - who in 1946 was already 70 years old - bore the burden of post-war rebuilding until the end of 1950, aided only by some of the old staff members. The restoration of the two surviving wings of the Museum was very slow and only more or less finished in the middle of the 1950s. Therefore it was not possible to appoint a new director before 1955. The scientific staff had been reduced to 8 persons. From 1950 to the present there were nine changes in the directorship. In addition to E. Werdermann (1892-1959), H. Melchior (1894-1984), and W. Domke (1899-), Th. Eckardt (1910-1977) who led the Botanical Museum for 13 years should be mentioned especially. His was the longest period of directorship after the war.
Since 1960 it was possible to enlarge the scientific staff to 17 botanists. However, the reconstruction of the building for the herbarium and library could not - despite of several attempts - be turned into reality. During the tercentenary celebration of the Berlin Botanical Garden in 1979 a new building was again promised and, finally, in 1987, under the directorship of W. Greuter, the collections were moved into the new wing.
The rebuilding of the herbarium was started soon after the 1943 destruction from some European collections that remained at Berlin (e.g., the herbaria of Engelhardt, Beger, and Bothe). The fast growth of the holdings of the Botanical Museum in the following years was only possible through generous gifts from friendly institutions and botanists. For example, specimens came from the collections of the Botanical Institute of the Faculty of Agronomy of the Berlin University and from the University at Marburg as well as large collections from Vienna. Other sources of new material were specimens generously sent as gifts or in exchange soon after the war from American and British herbaria. The large herbarium of Bornmüller, including many types especially from S. W. Asia, is one of the most important collections in the new Berlin herbarium (cf. Wagenitz 1960).
Collection trips organized by the Botanical Museum were for a long time taken only to European countries. Since 1972 several expeditions have been carried out in the Republic of Togo, to contribute to the exploration of this botanically relatively poorly known West African country. The result of this project, a "Flore analytique du Togo", was published in cooperation with the University at Lomé (Brunel et al. 1985).
The herbarium of the Botanical Museum Berlin-Dahlem (B) now contains about 3 million specimens. In the systematic section's pages, as well as under "Selected collections acquired" (see the herbarium menu) a survey of holdings of the different plant groups in the general herbarium is given, emphasizing the parts of the old collections that were saved in 1943 (cf. Hiepko 1978) which according to Sleumer (1949: 173) was estimated to be "more than half a million sheets."
Nevertheless it must be stressed that because of the confusion during and after the war this compilation cannot be complete and that it is necessary to check each individual case in the herbarium to be sure whether or not a type was saved.
[Text taken from P. Hiepko in Englera 7: 219-252, 1987; slightly modified]