CHROMOSOME COUNTS FOR SOME LYTHRACEAE SENS. STR. (MYRTALES), AND THE BASE NUMBER OF THE FAMILY

Summary Chromosome numbers of 12 genera and 13 species of the Lythraceae sens. str. were determined. Nine of 12 genera and 12 species are reported for the first time. An analysis of all published chromosome data including these new counts shows that 13 of 15 genera for which we could determine the base number have x = 8, and two remaining genera ( Peplis and Lythrum ) x = 5, thus confirming an earlier suggestion that the original basic number of the Lythraceae is x = 8. On the basis of evidence from chromosome number alone, Punica (x = 8) (Punicaceae) fits in well with the pattern of chromosome numbers in the Lythraceae, but Sonneratia (x = 9 or 11) and Duabanga (x = 12) (Sonneratiaceae) are more distinct and perhaps derived from a group ancestral to modern Lythraceae.