Die Brombeeren des Geldrischen Distriktes innerhalb der flora der Niederlande

This study deals with the taxa of the section Rubus of the genus Rubus L., so far as they are found in the Guelders district within the flora of the Netherlands. It concerns fifty species and some subspecies and varieties, mainly of the subsections Fruticosi Wimm. et Grab. and Discolores P. J. Müller. The similarity with the bramble-flora of northern Germany is obvious. A number of species, that occur in the latter region are absent however. Species of Central-European hills and mountains are as good as limited to the southern border of the Veluwe, which is mostly considered to belong to the Subcentreuropean district. South-European, often calciphilous species are absent. The nomenclature in the genus Rubus is very confused. There is an abundance of homonyms and synonyms. The number of misidentifications is rather large, meaning that a great deal of the literature is unreliable. The descriptions with many authors are absolutely insufficient, and type-specimens are often with difficulty or not at all to be traced. The difficulties arise from the fact that many taxa are not clearly separated. Some of them are well distinguishable, others are related by transitions. From a geographical point of view there is much difference as well. Some species have as their area almost the whole of Europe, others are limited to a very restricted area. In addition there is a difference in chromosome numbers (from diploids (2n = 14) to hexaploids (2n = 42). Most taxa are tetraploid. The abundance of forms within the section Rubus arises from a partly apomictic, partly amphimictic propagation. To set up some order in all those differences, the author has made the following distinctions: morphologically there are the different ranks of species and infraspecific taxa. Geographically distinctions have been made by means of a code of the capitals A to D inclusive: A indicates the taxa with the largest area, D the local taxa. Cytologically a code of Roman numerals has been given: I for diploids, II for polyploids. Beside the introductory theoretical part a short description of all taxa of the section above the specific rank has been given. All species and infraspecific taxa of this section, that are found to occur in the Guelders district have been described in detail, with mention of the type-specimen. Pictures have been added of the newly described taxa, and of some others as well. Maps of the distribution in the Netherlands of all the taxa have been inserted.