Hypericum canadense in Europe

Abstract

In 1935 the present author reported the occurrence of this N. American species in the eastern part of Holland, province of Overijssel, in the vicinity of Almelo (JONKER, 1935). He found the species near the hamlet of Harbrinkhoek on a wet heath. The locality was also the only station of Wahlenbergia hederacea in the Netherlands, discovered a year before. Notwithstanding the extensive reclamations in that part of the country the species now still occurs in a number of localities around Almelo. The plants cannot be considered adventitious as they were found in places that are comparatively little influenced by human culture, judging from the occurrence, on the first-discovered locality, of e.g. Wahlenbergia hederacea. Gentiana pneumonanthe, Viola palustris, Radiola linoides, Linum catharticum, Scutellaria minor. The late Dr. Wachter discovered, in the herbarium of the Royal Botanical Society of the Netherlands, unidentified specimens of Hypericum canadense collected by Lako as early as 1909 in the same environment, perhaps even in the same station; and Dr. van Soest identified two specimens collected in 1918 by the late naturalist Bernink near Denekamp, about 20 km E of the above mentioned localities. Bouchard (1953, 1954, 1955) reported the discovery of the species in France, dept. Haute-Saone. The plants were found in large quantities, at the stony beach of oligotrophous lakes, together with Littorella uniflora. In his detailed publication of 1954 he discussed the possibilities of introduction. He concluded that the plants are not adventitious. They may be autochthonous or naturalized and then, when the latter is the fact, probably by U.S. army units that stayed in that area during world war I. He did not preclude, however, the possibility of a glacial relic. Bouchard overlooked the previous publication reporting the occurrence in Holland.