14 STl'DIES IN INDIAN KIRRK PLANTS. 



Mixed lultmcs of this crop can often be detected in tlie seed- 

 ling stage. It was found that great care was necessary in thinning 

 to prevent the coolies and boys from removing all the seedlings 

 which differed from the bulk of the culture. If left to themselves 

 they invariably removed everytlung which differed fi'om the bulk 

 of the culture and so unconsciously rogued the plots. It was neces- 

 sary to watch the thmning of the cultures personally and to point 

 out which plants were to be removed. 



Every year cultures obtained from single fiee-flowering plants 

 were mixed and often contained individuals which diifered from 

 any of the types in cultivation at Piisa. In 1909, seed from a 

 large number of aberrant plants found in these single plant cul- 

 tures were collected and the seed of each plant was sown sepa- 

 rately. In every case the progeny was mixed. On the other hand 

 in 1910 no case of splitting was observed when seed of the types 

 described in the present paper was obtained under bag and sown. 

 Cross-fertilization in this species is therefore very common when 

 the various forms are grown next to next and allowed to Howcr 

 freely. A study of the methods of pollination in this crop shewetl 

 that the opportunities for cross-pollination by insects are very 

 great. 



The flowers of this species open in the early morning before 

 daybreak and begin to close about midday. The closing of the 

 flower is fairly rapid and l)ef()ie sunset the partially withered 

 corollas are twisted up in the manner shown in Plate I. 

 During the night still further twisting of the corolla takes place, 

 giving rise to the cottage loaf shape of the withered Hower shown 

 opposite. 



The method of pollination of the flowers of this species is of 

 considerable interest and does not seem to have been previously 

 studied in detail. When the flowers open, the stigmas are at the 

 mouth of the staminal column and the anthers have not yet com- 

 menced to l)urst. Soon after daybreak, the stigmas still remain 

 flush with the 'opening of the column. After this the turgidity of 

 the filaments falls olT and tin- buisl anthers bend liaek towards the 



