Abstract. P. Delforge.- Nomenclatural and taxonomical contribution to the genus Himantoglossum (Orchidaceae) [Natural. belges 80 (Orchid. 12) (1999): 387-408]. The mediterranean and submediterranean Barlia-Comperia-Himantoglossum constellation, formed of few robust species, globose tubered, with large flowers, is usualy divided into three genera. A taxonomic revision well supported by morphological, caryological, and recent molecular data suggest that it forms a single clade. Barlia has generally been considered as very closely related to Himantoglossum, the main reason to maintain Barlia as a genus seems to be the long nomenclatural uncertainties around Aceras-Loroglossum-Himantoglossum as generic name for the ĮLizard orchisČ, solved in 1972 by conservation of Himantoglossum W.D.J. Koch 1837. Comperia comperiana, a very rare oriental species, is considered since 1849 as the single species of an isolated genus, mainly because of the spectacular lengthening of the labellum lobes and the presence of 2 separated viscidia, as among Orchis, against one single viscidium among Himantoglossum-Barlia. In fact, that structure does not seem constant: personnal observations of Comperia fresh flowers have revealed that the 2 viscidia are most often so close that they work as a single viscidium, unlike the Comperia description by K. Koch (1849), reproduced by most authors. Thus, the Comperia column feature does not always differ structuraly from Himantoglossum-Barlia. Consequently, the maintain of the genus Comperia is not justified. New combinations are made for Himantoglossum robertianum, Himantoglossum metlesicsianum, and Himantoglossum comperianum. A parcimonious arrangement of the monophyletic genus Himantoglossum is attempted, with definition of the limits of 2 natural species groups based on consideration of features resolvable into discrete character states. The first, comprised Himantoglossum robertianum, H. metlesicsianum, and H. comperianum, has stigmatic cavity higher than wide, oblong stigmatic surface, glabrous maculated labellum with a middle lobe as long as the side lobes, or somewhat longer. It is probably derived from a taxon of the Orchis spitzelii species group, morphologicaly very similar. The second Himantoglossum species group, corresponding to Himantoglossum Sectio Euhimantoglossum Schlechter 1918, has stigmatic cavity wider than high, squarred or hemispheric stigmatic surface, and labellum with middle lobe much longer than the side lobes. Into that species group, a subgroup, most derived, comprising of Himantoglossum caprinum, H. adriaticum, and H. hircinum, has a labellum center orned with brushes of purple pilosity; the 2 other species of the group, H. affine and H. formosum, closer to H. robertianum, are characterized by a glabrous white labellum center with a less long middle lobe. The group is also probably reticuled by one or two hybrid taxa with controversed status: H. montis-tauri and H. samariense, intermediary between H. affine and H. caprinum.

Key-Words: Flora of western Palearctic. Orchidaceae, Orchidoideae, Serapiadinae. Genus Himantoglossum, Barlia, Comperia. Himantoglossum robertianum comb. nov., Himantoglossum metlesicsianum comb. nov., Himantoglossum comperianum comb. nov.