ALBERT AND GABRIELLE HOWARD. /5 



imately equal in length, and this is the most usual arrangement, 

 or one may be shorter than the othei' three, or there may be 2 

 lono- and 2 short stamens. 



Pollination may take place in the closed bud or, as is more 

 frequently the case, the anthers burst just as the bud unfolds. In 

 a few cases the anthers burst later when the flower is half ex- 

 panded. In the time of pollination this species differs from 

 Nicotiana rustica in whicli pollination generally takes place 

 just before the bud opens. 



The relative position of the anthers and stigma and conse- 

 quently the certainty 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 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 

 the fully opened flowers the burst anthers and stigma may 

 maintain this relative position or the anthers may be as much as 

 5mm. above the stigma. In some cases the ripe anthers are 

 well above the stig-ma in the unfoldino^ bud, and in such cases 

 the burst anthers are always far 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 striking difference was observed in the position of 

 the stiofma and anthers with regard to the orifice of the corolla. 

 In some cases the anthers or stigma project far beyond the 

 corolla opening. This can be seen in the front view of the corolla 

 of type II (Plate III) and of type IX (Plate XII). In other 

 cases the anthers or 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. 



In the majority of the Indian types of N. tahacum, self-pol- 

 lination is somewhat more favoured than cross-pollination, but in 

 none of the types so far examined is crossing practically excluded 

 as in type Vof N. rustica where the stamens are massed so closely 



