TY - JOUR T1 - Exotische muurvarens in Belgiƫ en Nederland JF - Dumortiera Y1 - 2007 A1 - Filip Verloove A1 - Raymond van de Ham A1 - Ton Denters SP - 1 EP - 16 AB - Exotic mural ferns in Belgium and the Netherlands. In recent years an increasing number of exotic mural ferns have been recorded in urban areas of Belgium and the Netherlands. Without exception, these plants have escaped from cultivated individuals of which tender taxa bave profited by microclimate and environmental conditions present in larger cities ('heat islands'). The present paper deals with recent records of Adiantum capillus-veneris, A. diaphanum and A. raddianum, Cyrtominm falcatum and C, fortunei, Dryopteris cycadina, Polystichum tsus-simense, Pteris cretica s.l. and P. multiflda. Most of these taxa are (very) frost-sensitive and their appearance may be temporary (Cyrtomium falcatum in the Netherlands excepted). Identification keys, photographs, original line drawings and herbarium scans are presented here for most of the escaped species to facilitate identification. In addition, distributional records and ecological comments are provided and reasons why the sudden increase in occurrence of exotic ferns in urban areas discussed. VL - 92 ER -