HOWARD, HOWARD AND ABDUR RAHMAN. 313 



2. Patwa. (Hibiscus Cannabinus, L.) 

 A large number of cultures of the fibre-yielding plant known 

 locally as pativa {Hibiscus cannahinus) have been grown in the 

 Botanical area at Piisa during the last four years, and some atten- 

 tion has been paid both to the method of pollination and the 

 occurrence of natural crossing. 



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 before sunset the partially withered 

 corollas are twisted up in the manner shown in Plate VII. During 

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

 rise to the cottage loaf shape of the withered flower shown 

 opposite. 



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

 considerable interest and does not seem to have been studied in 

 detail previously. When the flow^ers open, the stigmas are at the 

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

 menced to burst. Soon after daybreak, the anthers burst and 

 are covered by the large echinulate pollen, the stigmas still remain- 

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

 of the filaments falls of! and the burst anthers bend back towards 

 the column. Simultaneously the styles elongate and carry the 

 stigmas into the air beyond the opening of the column, and at 

 this stage pollen grains are rarely seen on the stigmas. Sometimes, 

 however, the styles bend outwards and carry the stigmas on 

 to the pollen, thus bringing about self-pollination. Frequently 

 no pollen is seen on the stigmas when the flowers begin to close 

 about midday. If closed flowers are, liowever, carefully opened, 

 it is found they are always well pollinated. Self-pollination is 

 effected almost entirely by the closing of the corolla. The limb 

 of the petal is thin, the claw very thick. The corolla closes by the 

 falling towards the centre and twisting of the thin limbs. This 

 brings the corolla in contact with the burst anthers and the 

 completion of the closing of the flowers covers the stigmas with 

 pollen. (Plate VII.) 



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