MORPHOLOGICAL VARIATION ALONG AN ALTITUDINAL GRADIENT IN THE MICRASTERIAS-CRUX-MELITENSIS M-RADIANS COMPLEX (ALGAE, ZYGNEMAPHYCEAE, DESMIDIALES) FROM PAPUA-NEW-GUINEA

Six populations of the Micrasterias radians-M. crux-melitensis complex from different altitudes in Papua New Guinea are studied. Principal c omponent analysis and discriminant analysis show the existence of thre e separate groups, distinguished mainly by the shape of the apex, the degree of incision and the opening of the sinus. The groups represent an altitudinal gradient corresponding with a transition from M. radian s in the lowlands to M. crux-melitensis at high altitudes.