ORIGINAL ARTICLE Anther wall and pollen development in Ophrys mammosa L. (Orchidaceae) Mehmet Aybeke Received: 23 December 2011 / Accepted: 11 February 2012 / Published online: 2 March 2012 Ó Springer-Verlag 2012 Abstract The objective of this study was to investigate anther wall and pollen development in Ophrys mammosa. Primary sporogen tissue resembles longitudinal cells with divided archeosporal cells. Thereafter these primary sporogen tissue cells re-divide anticlinally and periclinally forming secondary sporogen tissue. Microsporogenesis was successive type. Microgametogenesis occurred at the distal poles of the microspores. In addition, dense starch accu- mulation was detected in the pollen. Pollinia and massulae are separated from each other by dead cells filled with callose, according to histochemical preparations. The anther wall was a four-layered ‘‘monocotyledon’’ type. There was ring-like wall thickening in the endothecium. The tapetum is of the glandular type. When these two developmental processes are compared, it is seen that the anther wall has become mature by the sporogen tissue phase and is composed of only epidermis and endothecium at the beginning of microgametogenesis. Keywords Orchid Á Ophrys Á Anther wall Á Pollen Á Pollinium Introduction The Orchidaceae family has been the subject of numerous morphological works. Problems with the orchids originate mainly from the complicated morphological traits of hybrids, and from morphological variations in flowers, different pollen tectum features, and several pollination mechanisms (Tutin et al. 1968; Williams and Broome 1976; Paulus and Gack 1990; Rossi et al. 1992). So far in our work, Ophrys taxa have been investigated with regard to morphological, palynological, chorological, caryological, and anatomical factors, but not embryological factors (Sezik 1969, 1984, 1988; Aybeke 1997, 2000, 2002, 2004, 2007a, b; Aybeke et al. 2010). Because of the presence of many different embryological developments in the Orchidaceae family their taxonomic importance has been emphasized (Johansen 1950; Sharma and Vij 1987; Sood and Sham 1987). For example, most monandrous orchid pollen grains occur as tetrads in massulae that are united in a large structure, the pollinium. In other words, the pollinium is a big cell cluster in which small cell clusters are called massulae. Additionally, Maheshwari (1964) elaborated anther wall development and post-anthesis wall properties because of its taxonomic importance. When scanning the literature, it was seen that, in general, anther development in the Orchidaceae family was of a monocotyledon type, the anther wall was mainly five-layered, and microsporogenesis was realized by simultaneous cytokinesis, but no work was found on Ophrys embryology (Swamy 1949a, b; Davis 1972). Ophrys mammosa has been used in this study because it is the most problematical taxon in Turkey and Mediter- ranean countries. So, our efforts contribute to both Ophrys taxonomy in a major sense and to Ophrys mammosa embryology in a minor sense. The objective of the study is, therefore, to investigate anther wall development and pollen development. Materials and methods Ophrys mammosa plants growing in nature were used for embryological observation. Voucher specimens were M. Aybeke (&) Department of Biology, Faculty of Science, Trakya University, Balkan Campus, 22030 Edirne, Turkey e-mail: mehmetaybeke@yahoo.com 123 Plant Syst Evol (2012) 298:1015–1023 DOI 10.1007/s00606-012-0610-z