Microspecies of the Portulaca oleraceae aggregate found on major Mediterranean islands (Sicily, Cyprus, Crete, Rhodes)

The 178 samples belonging to the Portulaca oleracea aggregate, originating from Sicily, Cyprus, Crete, and Rhodes, seed size and seed coat micromorphology have been studied. The material was found to belong to 9 different microspecies, 5 of which are described as new to science. This raises the number of microspecies known in the aggregate to 15: 6 hexaploids (5 present in the area), 4 tetraploids (all present), 2 diploids and 3 uncounted (none present). A key for identification of all 15, based on seed coat characters, is presented and is illustrated by SEM micrographs for 14 of them.