ALBERT AND GABRIELLE HOWARD. 11 



just before the corolla opens, while in the fully-opened flower the 

 empty anthers are clustered round the style just below the stigma. 

 In a few types the anthers may just touch the stigma and the 

 pollen is deposited at its extreme edge or else beneath it. In such 

 cases the anthers are sometimes rather late in bursting and very 

 little pollen is shed before the flower opens. 



It is clear that very small difl'erences in the length of the 

 stamens w^ould produce any of these three conditions, and it is not 

 surprising to find that a certain amount of diflerence can some- 

 times be found in the flowers of the same plant. For instance, in 

 plants where the anthers normally just touch the stigma, it is 

 usual to find som^ flowers in which they escape touching it. 

 Thus, in some flowers cross-pollination would be more favoured, in 

 others self-pollination. 



Class III. — Style much loiif/e)- than the stamens. 



This extreme condition in which the stigma grows out of the 

 unopened bud into the air and in which self-pollination is exceed- 

 ingly difiicult was only met with in type I. In this type and also in 

 types VI, VII and VIII very few capsules naturally set seed, and 

 it was only possible to obtain seed under bag by artificial selfing. 



These observations point to the likelihood of the frequent 

 occurrence, under Indian conditions, of natural cross-fertilization 

 in the field when the t3^pes are grow^n next to next. That natural 

 crossing actually does take place under these circumstances was 

 proved in a large number of cases. 



Natural Cross-Fertilization. 

 During the year 1905 a collection of Indian tobaccos was 

 made by the Piisa Farm, and the sowings were made the same 

 year. A few plants of each sowing were allowed to run to 

 seed without being bagged, and this seed was again sown in 

 the autumn of I'JOG. In 1907, we selected seed from all the 

 diftercnt plants that could be found in these sowings, and the 

 seed from each plant was sown separately by us the same 

 year. Opportunities for natural cross-fertilization at Piisa were 

 therefore possible for two seasons, 190G and 1907, before we took 



