Sub-haploid pollen inPaphiopedilum insigne (Orchidaceae)

Sub-haploid pollen grains with chromosome numbers ranging from n = 5-12 were seen in the cultivar ‘Maulei’ ofPaphiopedilum insigne Pfitz. Many grains showed n = 5 and 6 (38%) while 3% showed a hyperploid number (n = 18, 20). It was also observed that pollen grains with the same chromosome number differed in karyotype. The high percentage (81 %) of sub-haploid pollen grains in the present case may be due to the high degree of segregational irregularities during meiosis or to split spindle or failure of wall formation. It may also be due to changes in the environment of the species which may influence the metabolic activity responsible for the initiation and subsequent development of the cell wall and the process of chromosome duplication.