Abstract. Devillers, P. & Devillers-Terschuren, J.- Phylogenetic notes on some Ophrys of the Ophrys fusca s.l. complex in the central Mediterranean [Natural. belges 81 (Orchid. 13) (2000): 298-322 + 9 figs]. Genus Ophrys illustrates in a particularly evident way phenomena of radiation by floral differentiation, with bottlenecks, founder effects and abrupt cladogenesis essential to the diversification of the Orchidaceae. In the Ophrys fusca complex, these processes are expressed by a great microdiversity of floral details characterising relatively homogeneous swarms, separated or not in space or time, against a background of considerable overall similarity, even at the level of floral appearance. Part of this variation corresponds to an adaptation to different pollinators, a long-known mechanism, notably expressed by differences in size. The recourse to different pollinators clearly carries with it an isolation factor pre-eminent in the case of sympatric populations. The exclusive emphasis upon it, that has even gone so far as to designate the plant by its pollinator, masks, however, the possibility of multiple adaptations to the same pollinator from lineages phylogenetically distinct yet morphologically close. Such multiple adaptations are obviously possible, without rupture of interspecific barriers, in the case of allopatric populations. It is also possible in sympatric taxa, for instance if the precise floral geometry introduces an isolation mechanism in the positioning of the pollinia on the pollinator, or if distinct flowering periods correspond to different segments of the pollinator population. Understanding of these phenomena requires a correct understanding of the various morphologically distinct taxa and of their probable affiliation to lineages. The note attempts to clarify the characters of a number of species of the central Mediterranean basin, mostly characterised by small or medium flowers and that have been, at one time or another, associated to the widely known O. bilunulata and O. funerea, and to situate them with respect to three lineages that we had recognised earlier, those of O. fusca s. str., O. funerea, and O. obaesa. The first of these lineages is best characterised by strong relief at the base of the macula, a macula that is not divided by a pilose or grooved line, and a uniform density of the pilosity outside of the macula. Two small-flowered species are discussed, O. forestieri of southern France and O. gazella of Tunisia, which is newly described. The medium sized species, O. bilunulata, is briefly evoked. A large-flowered form of Monte Argentario, which offers some resemblance to O. bilunulata as well as to O. fusca s. str., is described as O. lucifera. The second lineage has little relief at the base of the macula, a macular divider similar to the perimacular area and usually pilose, a clearly zonated labellum pilosity. Three small-flowered species, O. funerea, O. punctulata, O. hespera, two medium sized ones, O. zonata and O. leucadica, and one large-flowered one, O. arnoldii, are considered. Of these, O. punctulata and O. leucadica of Ionian Greece have long been described but their relationships to other taxa of the group is reconsidered and reformulated. O. hespera of Monte Argentario, captured island of the Tuscany archipelago, is newly described. It appears fairly similar to the Cyrno-Sardinian endemic O. funerea but has probably an independent phylogenetic origin. O. arnoldii, for which new stations are noted in France, is mentioned because of the existence within its possible range of variation of very narrow-lipped swarms that may induce confusion with small-flowered species of the group. The taxonomic status of these is unresolved and still under investigation. The third lineage, that of O. obaesa, combines a strong relief of the upper surface of the labellum, in particular in the region of the base of the macula, with a grooved, glabrous or ciliated macular divider and a somewhat variable but often extensive zonation of the labellum pilosity. One particularly distinctive North-African and perhaps Maltese species that appears to belong to the group is discussed and the adequacy of using for it the longstanding name O. pectus is supported. Its characters contribute to forging for the O. obaesa lineage the image of a central group separately related to both the O. fusca and O. funerea lineages on the one hand, to the O. subfusca group and thus the O. lutea complex on the other.

Key-words: Orchidaceae, genus Ophrys, Ophrys funerea, Ophrys punctulata, Ophrys hespera, Ophrys forestieri, Ophrys gazella, Ophrys bilunulata, Ophrys zonata, Ophrys leucadica, Ophrys pectus, Ophrys fusca, Ophrys lucifera, Ophrys arnoldii, France, Italy, Greece, Tunisia, Corsica, Sardinia, Ionian Islands.