Abstract. Delforge, P.- Orchids of Wallonia - Appraisal of the situation of thirteen species  threatened or needing particular attention [Natural. belges 79 (Orchid. 11) (1998): 131-200]. Research in Wallonia (southern Belgium) and numerous observations during 10 years by various authors and members on the ÇSection OrchidŽes d'Europe des Naturalistes belgesČ within the framework of covenants with the Walloon region for an environmental monitoring based on bio-indicators have led to a reappraisal of the occurrence of the Walloon orchid species. The present paper describes the situation and the dynamics of the 13 most endangered of them with an updated list of the present localities and a distribution map. It specifies also their legal status, mentions possible protection measures and evokes their present situation in the adjacent regions: Brussels-Capital region, Flemish region, The Netherlands, western Germany, Luxembourg and northern France.

Key-Words: Flora of Wallonia, Belgium, The Netherlands, western Germany, northern France, Luxembourg; Nature protection; Orchidaceae, Epipactis microphylla, Epipactis leptochila, Cephalanthera longifolia, Limodorum abortivum, Spiranthes spiralis, Corallorrhiza trifida, Liparis loeselii, Hammarbya paludosa, Gymnadenia odoratissima, Dactylorhiza incarnata, Dactylorhiza sphagnicola, Orchis ustulata, Ophrys sphegodes.