Abstract
In Japan, formerly the leading species was Pelargonium denticulatum. For .the purpose of increasing oil production, three types of P. roseum were introduced in 1954, viz., varieties "Italy", "France" and "America". The present paper deals with morphological and physiological properties as material plants and chemical composition of essential oil. The results are summarized as follows: (1) The leafblade of P. roseum varieties is broader than that of P. denticulatum (Fig. 1). There are no marks in petals of P. roseum "America", of which petiole and internode are short. (2) There are no significant differences in the distribution of oil gland and the percentage of oil among three varieties of P. roseum. The average yearly oil yield of P. roseum is around 0.1 per cent, that is as low as about a half of that of P. denticulatum (Fig. 2 & 3). (3) P. roseum plants are more spreading and shrubby with vigorous growth than P. denticulatum, but in the former the yearly yield of oil per hectar is low. (4) In the oil of P. denticulatum, the acid number and the ketone content as isomenthone are very high, and the ester content as tiglates is very low. The chemical properties of Italy type oil resemble those of France type oil. America type oil is relatively high in acid number, ketone content and ester content. The oil of P. denticulatum is inferior to P. roseum in quality (Table 2 & 3).
