Abstract. Delforge, P.- Contribution to the knowledge of the Orchids of the island of Rhodes (Dodecanese, Greece): Ophrys colossaea sp. nova [Natural. belges 87 (Orchid. 19) (2006): 201-216]. The fucifloroid ophrys of Rhodes are briefly revised in the light of a field trip of 7 weeks in the island in 2006. A large- and late-flowering taxon of the Ophrys heldreichii species group, pollinated by Eucera dalmatica, is described as Ophrys colossaea. It had previously been known as O. apulica, O. episcopalis, O. fuciflora vel holoserica s.l. or O. maxima. A list of 15 localities attributable to O. colossaea, based on prospections in Rhodes in 1984 and 2006, is provided.

Key-Words: Orchidaceae, genus Ophrys, Pseudophrys, Ophrys heldreichii species group, Ophrys colossaea sp. nova. Flora of Greece, island of Rhodes (Dodecanese).