POLLEN MORPHOLOGY OF ORYZA (POACEAE)

Pollen morphological studies of 19 species of Oryza (Poaceae) were car ried out using LM and SEM. Eleven exine surface patterns are distingui shed at x20,000 magnification under SEM. These are categorised into th ree basic types: granulose, spinulose and insular. O. brachyantha- a g enomically unrelated species, and two species (O. granulata and O. mey eriana) comprising the O. meyeriana complex have spinulose exine surfa ces. The O. ridleyi complex which also contains two species (O. longig lumis and O. ridleyi) is characterised by a granulose exine pattern. I n the O. officinalis complex and the O. sativa complex, both granulose and insular exine patterns have been observed in different species. T he largest pollen grains occur in the O. sativa complex, which contain s both cultivated species and their wild relatives.