Rubi in the Northeastern part of the Netherlands (A floristic and vegetational study) BY W. Beijerinck AND A.J. ter Pelkwijk Communication 55 the nr. of Biological Station, Wijster (Dr.) Contents: page: I. Introduction 325 II. The Drenthian District 328 III. The method of investigation 331 IV. The Rubus-flora of the Drenthian District 333 V. Distribution of the species 337 The in which the Rubi VI. plant-communities occur 346 VII. Comparison with the Rubus flora ofother phyto-geographical districts in the Netherlands 354 VIII. with the Rubi of the of 356 Comparison adjoining parts Europe . IX. Summary 358 X. References 359 “The almost inexhaustable of power nature to vary is illustrated this very beautifully by differentiation of the blackberry populations into innumerable local floras. Gustafsson l.c. (A. (1943), p. 156) I. Introduction There in the is no uniformity geographical distribution of the various European Rubus species and not only the main phyto- districts but much smaller to geographical even areas appear possess their combinations of A of the available data own species. survey has been given in 1943 by A. Gustafsson in his fine book: “The genesis of the European Blackberry Flora”. The knowledge of the distribution of the brambles within the Netherlands at that time distinctly lagged behind that of their distribution in the surrounding countries, viz. in N. W. Germany, Belgium, Great Britain and Scandinavia, where the investigations of serious had various batologists already laid a sound foundation. In N. W. Germany the pioneer work of K. E. Weihe and C. G. Nees von Esenbeck (1822—1827) had been followed by the painstaking studies of W. O. Focke, Bremen, that were continued for more 326 W. BEIJERINCK AND A. J. TER PELKWIJK than 60 and led valuable into the distribution years to a insight of the various species. Another result of these studies was the description and classification of and forms that far had been many species so overlooked or that were unsufficiently known. Focke’s lifework has become a classic in its, kind. It has laid the the foundation for a more exact knowledge of European brambles, a branch of science, in which so much amateurish work has been done had The local that it got into utter confusion. number of forms of which descriptions had been published had become enormous and the themselves often descriptions were unsatisfactory. The singling out among the overpowering wealth of forms (Focke’s of with “Formen-Schwarme”), species a larger area of distribution, the merit of this who be was great investigator, may acknowledged as the first batologist with modern views. His numerous publications between the 1868 and 1914. appeared years For Belgium we have at our disposal a paper published by A. Charlet, L. Magnel and A. Marechalin 1928 and for England the publications of C. C. Babington (1846, 1869), W. M. Rogers (1900), H. J. Riddelsdell (1920) and W. Watson (1946). A of the Scandinavian Rubi Sweden and survey (Norway, Denmark) is given in the studies of C. E. Gustafsson (1938) and A. Gustafsson (1943). The most on the distribution of complete report species up to 1913 is to be found in H. Sudre’s big monograph: “Rubi Europae” (1908 —1913). The classification given in this standard work has in the main been followed by us. In the Nederlandsch Kruidkundig Archief, 13 (1903) L. Vuyck of in gave a list Rubus species that might be expected the Netherlands been the or had already collected there. This list was based on work of Focke. In 1919 H. Heukels, in his “Flora van Nederland” of the that known that and gave descriptions species were at time, a list of these species is found also in the 11th edition of the “Geillustreerde Nederland” Heukels and Wachter. This Schoolflora voor by list, several however, is by no means complete and it contains moreover errors. Further be here the A. Wever may mentioned notes by de on the brambles of the southern part of the province of Limburg (1915). His and Sudre. specimens were revised by Focke by Moreover under the heading: “Nieuwe vindplaatsen” (in: “De Levende Natuur” and in “Nederl. Kruidk. Archief” and in several other places in the latter periodical (i.a. in the excursion reports of the the of various hitherto Rubi K.N.B.V.) presence unreported has been mentioned. Extensive bramble collections are found in the larger herbaria in the Netherlands, in particular in the “Rijks- herbarium” and in the herbarium of the K.N.B.V. at Leyden. The naming of these collections was not always satisfactory but a large the Kern and part of specimens has now been revised by us. J. H. Th. Reichgelt have started with of the compilation our knowledge of the Dutch Rubi for the “Flora Neerlandica”. Much aid has been RUBI IN THE NORTHEASTERN PART OF THE NETHERLANDS 327 thankful. given to us by these two botanists, to whom we are truly Our first contribution to the knowledge of the brambles of the Netherlands appeared in 1950: “De voornaamste bramen in het Drentse District”; in this publication 20 species were enumerated and discussed, and a key to these species was given. It is our intention to continue this series of contributions with separate studies of the most important bramble centra in our country, and also with other this of papers on questions relating to group plants. They are meant as preliminary steps to a monograph of the brambles of the Netherlands. The third contribution, will give a of the brambles in the complete survey occurring phyto-geographical Drenthian district; it will also contain a number of new findings. in This district has already proved to be rich species that are rare or absent in other parts of the country. We hope that this fourth contribution which deals not only with floristic details but also with the distribution of the species and with the part they play in various plant communities, will rouse interest in this and and its multifarious an vast engaging genus problems. Netherlands Fig. 1. Phyto-geographical districts of the (after J. L. van Soest; slightly changed) borders of the districts. Dotted = Drents district (“Drenthian district”). I Fluviatiel district. II Haf district. Ill Gelders district. IV Subsentreuroopdistrict. V Kempens district. VI Krijt district. VII Duin district. VIII Wadden district. IX Loss district. X Vlaams district. 328 W. BEIJERINCK AND A. J. TER PELKWIJK II. The Drenthian District The area that forms the subject of this study extends in the east far as as the German frontier and is bordered in the N.W. and S. by an imaginary line drawn from Nieuweschans past Groningen, Dokkum, Leeuwarden, Heereveen to Dalfsen and from here eastward the along the valley of river Vecht past Marienberg to Almelo and It and Oldenzaal. includes moreover Gaasterland, Vollenhove parts of Wieringen and Texel (Fig. 1). Characteristic for this area, which the Dutch plantgeographers call the “Drenthian District” are loamy sands resting on a slightly undulating ground moraine. In a former period these deposits must have been covered by this is the of extensive stagnant water; proved by presence peat formations, which reach to the soil’s surface, and by that of hardpans in the sands themselves. The district Comprises in the first place sands and loams, marshes, moors and brook deposits, but not the clays that are here and there found transgressing its boundaries. The surface of this weakly undulating landscape lies between ± 0 and 25 m above sea level (“N.A.P.”). On the map of the stations where the bramble flora was studied (Fig. 3), the river systems have been indicated and also the provincial borders, the railway Zwolle— Groningen and the principal villages. The Angiospermous flora of this district contains northern (boreal and montane) as well as atlantic elements. According to H. Walter (1927) the following species belong to firstnamed the category: Andromeda Polifolia L. Parnassia palustris L. Arnica montana L. Phyteuma nigrum Schm. Cornus suecica L. Polygonatum verticillatum All. Empetrum nigrum L. Rubus saxatilis L. L. Goodyera repens R. Br. Scheuchzeria palustris Linnaea borealis L. Sparganium affine Schm. Lysimachia thyrsiflora L. Stellaria nemorum L. L. Lycopodium annotinum L. Trientalis europaea Majanthemum bifolium W. Schn. Vaccinium Myrtillus L. Nardus stricta L. Vaccinium Oxycoccus L. Paris quadrifolia L. Vaccinium Vitis-idaea L. The atlantic of group species comprises; Corydalis claviculata Lam. et DC Lobelia Dortmanna L. Erica Tetralix L. Hammarbya paludosa O. Kuntze Galium saxatile L. Cicendia filiformis Delarb. Genista anglica L. Myrica Gale L. Genista pilosa L. Narthecium ossifragum Huds. Hypericum elodes L. Pedicularis sylvatica L. Ilex Aquifolium L. Primula acaulis Grufb. Illecebrum verticillatum L. Sarothamnus scoparius Wimm. RUBI IN THE NORTHEASTERN PART OF THE NETHERLANDS 329 On the whole there is a close connection with the flora of N.W. other Germany; Central-European species on the hand, are rare. known and Many species that are from Germany, France Belgium, and that are also met with in the southern part of the Netherlands absent. are altogether In topographical respect it is noteworthy that the district shows differences in the no important level, surface sloping gradually to the N. and S.W.. the of The valleys formed by brooks are shallow but often great width. Along and within these valleys remains of the Alnetum and of the Querceto-carpinetum are still to be found; and although the of these be often harbour extent rests may very small, they a very remarkable flora and fauna. the and The long-established coppice woods as well as hedges the often luxurious scrub along ancient country and cattle tracks, the so- called also contain of the “Drentse wildgroei” may rests original flora, i.e.