A STUDY OF THE VARIATION IN THE ESSENTIAL OIL AND MORPHOLOGY OF PELARGONIUM-CAPITATUM (L) LHERIT (GERANIACEAE) .3. GEOGRAPHICAL VARIATION IN ESSENTIAL OIL COMPOSITION AND FLORAL STRUCTURE

Pelargonium capitatum (L.) L'Herit, is one of the parent species of th e cultivar Rose grown on the Island of Reunion for its essential oil. The ultimate aim of this project is to identify chemotypes which could be included in hybridization programmes to ennoble the cultivar Rose. Forty populations of P. capitatum were selected along the west and ea st coasts of South Africa to describe the essential oil and macromorph ological diversity in relation to geographical distribution. A multiva riate statistical analysis was performed on the essential oil data. A survey of the composition of the volatile oils proved the species to d isplay high levels of essential oil variation which allows for the spe cies to be divided into chemotypes correlating to geographical distrib ution. No clear-cut macromorphological discontinuities were apparent b etween populations, but an obvious congruence between the essential oi l composition and macromorphology was accentuated in extreme cases.