Chromosomal observations on Eliea (Hypericaceae), a monospecific Madagascar endemic

A meiotic chromosome number of n=9 is reported for Eliea articulata, a monospecific genus of Hypericaceae endemic to Madagascar. This first report for the genus is a new number for the small tribe Cratoxlyeae which includes only one other genus, Cratoxylum. A hypothetical scenario for the origin of n=9 is provided in the context of known chromosome numbers for Cratoxylum and the two other tribes in the Hypericaceae. Given that x=12 has been proposed as the basic chromosome number for the family with numbers of n=11 and n=10 also reported for related species and genera, n=9 appears to have arisen as a descending dysploid from these higher numbers. Field photos of Eliea articulata are provided along with a distribution map and camera lucida drawings of meiotic chromosome figures.