ABSTRACT
The castor bean plant, Ricinus communis L., is the only member of its genus and belongs to the family Euphorbiaceae. The plant is cultivated in tropical, subtropical, and temperate countries, mostly for the oil which forms 45 to 55% of the ripe seeds. The time of flowering, i.e., the relative earliness or lateness of a plant or variety, is best expressed by the number of nodes on the main stem below the primary inflorescence. This may range between 5 to 6 in extremely early types up to several tens in palm-like, very late plants. The sexual balance, male/female, may vary within the inflorescence or between inflorescences on the same plant. A collection of plants from three countries in the Far East was grown in Japan under natural and 16-hr-day conditions and found to vary in sensitivity to day length.
