310 NATURAL CROSS-FERTILIZATION IN INDIA. 



place in the closed bud and in a few cases the anthers burst later 

 when the corolla is half expanded. 



The relative positions of the anthers and stigma and conse- 

 quently the likelihood of self-pollination varies in the different 

 types. The anthers may be below the stigma when they burst 

 and may remain always at a lower level than the stigma making 

 cross-pollination very probable, but this condition is rare. The 

 most usual arrangement is that in which the ripe anthers surround 

 or are just above the stigma when the flower opens. In these cases 

 both cross and self-pollination are possible. In the fully open 

 flowers the burst anthers and stigma may maintain this relative 

 position or the anthers may be as much as 5 mm. above the stig- 

 ma. In some cases the ripe anthers are well above the stigma in 

 the fully open flower. In one or two types cases were found in 

 which the ripe anthers surrounded the stigma but the latter was 

 well above the empty anthers later. 



Another dift'erence was observed in the position of the stigma 

 and anthers with regard to the orifice of the corolla. In some cases 

 the anthers and stigma project into the air far beyond the corolla 

 opening. In other cases the anthers and stigma remain low down 

 in the tube of the corolla. In the majority of the types the 

 anthers are either level with the corolla orifice or project slightly. 



The arrangements for pollination in the various Indian types 

 differ somewhat. The majority of the types readily set seed under 

 bag but a few set only it self-pollinated. 



Most observers agree that natural cross-fertilization occurs 

 in this species but the extent to which it takes place when the types 

 are grown next to next does not appear to be realised fully. The 

 collection of Indian tobaccos made at Pusa in 1905 was grown for 

 two years on the Piisa farm and a few plants of each kind were 

 allowed to flower freely in 1906 and again in 1907. In 1907, we 

 selected all the different types in this collection, and saved the seed 

 from each plant separately. The various sowungs were made by us 

 in the Botanical area at Pusa the same year, and since that time all 

 seed used to propagate the types has been raised under bag. Oppor- 



