314 NATURAL CROSS-FERTILIZATION IN INDIA. 



It will be seen that the flowers are adapted both for cross and 

 self-pollination. From the time the styles begin to carry the 

 stigmas beyond the opening of the column to the closing of the 

 flower crossing is possible. Self-pollination, however, may occur 

 during this period. A sufficient supply of seed is ensured by the 

 very effective method of selfing when the flower closes. 



The flowers of this species do not set seed under bag in the 

 ord'nary way unless artificially self-pollinated. This is due to the 

 fact that the flower closing mechanism does not act in the bag. 

 The thin limbs of the corolla do not fall together and twist in the 

 normal manner possibly on account of the even humidity of the air 

 both outside and within the closing corolla. 



Cross-fertilization is fairly common in this species when the 

 various types are grown next to next and allowed to flower freely. 

 Aberrant plants were found in nearly all the plots raised from the 

 seed of free flowering plants in 1909. These were sown separate 

 early in 1910. In all cases they split up into forms with entire 

 and divided leaves and with variously coloured red and green stems. 



3. EosELLE. (Hibiscus Sabdariffa, L.) 

 Natural cross-fertilization does not appear to be equally com- 

 mon in all the cultivated species of the genus Hibiscus. Several 

 varieties of Roselle, Hibiscus sabdariffa, have been grown next to 

 next at Piisa for four years and not a single instance of natural 

 crossing has been observed even at the edges of the plots where 

 the plants of the varieties touch. Year after year the varieties 

 come true and no crossing has been noticed. The flowers appa- 

 rently always self-fertilize themselves. The flowers of this species 

 open late in the morning and close at midday remaining open 

 for not more than three hours. The stigmas are throughout flush 

 with the opening of the column and do not grow into the air as 

 in the case of Hibiscus caymabinus. The filaments are very short 

 and the anthers burst round the opening of the column. Self-polli- 

 nation is favoured by these arrangements and the completion of the 

 process is brought about by the closing of the flower. (Plate VIII.) 



