Rudrakshi has common pumello sized fruits with smooth rind and less spines, whereas Singapore or Ceylon jack, introduced from Ceylon, is highly precocious.The 'Singapore', or 'Ceylon', jack, a remarkably early bearer producing fruit in 18 months to 2 1/2 years from transplanting, was introduced into India from Ceylon and planted extensively in 1949. The fruit is of medium size with small, fibrous carpers which are very sweet.