Abstract
This paper presents a cytological study of two recently described species of Ophrys from the Apulia region, which is one of the most important diversification centres of the genus. The basic chromosome number was x = 18 for the two species. Ophrys peucetiae Lozito, D'Emerico, Medagli & Turco has the karyotype 2n = 2x = 36: 24 m+12 sm, and O. pseudomelena Turco, Medagli & D'Emerico has 2n = 2x = 36: 30 m+6 sm. As observed in the O. fusca group, in O. pseudomelena, metacentric chromosomes predominate over submetacentric ones. In contrast, Ophrys peucetiae has a more evolved character, as seen in the standard karyotype of O. fuciflora s.l. On average, Ophrys peucetiae exhibited a more asymmetrical karyotype than O. pseudomelena. Variations in morphology and size in chromosome pair 1 were observed within both species. Studies on chromosome numbers in Ophrys taxa from Apulia and Sardinia revealed triploidy in Ophrys morisii (Martelli) Soò and tetraploidy in O. apulica (O. Danesch & E. Danesch) O. Danesch & E. Danesch and O. forestieri (Rchb. f.) Lojac. ( = O. lupercalis Devillers Tersch. & Devillers). The significance of the results is discussed in relation to previous information for this genus.
Acknowledgement
The authors would like to thank Prof. Antonio Scrugli for providing the samples of O. morisii from St. Castiadas-Solanas (Cagliari).