10 STUniKS IN IN 1)1 AN TOBACCOS. 



l)urst ill tlie bud before the corolla opens and that the stigma is 

 receptive at the same time. Homogamy is therefore the rule. 

 The relative position of the stigma and anthers, however, was 

 found to vary considerably between the various types. The 

 general scheme was found to be as follows. The anthers just 

 before the flowers open are either below, opposite or above 

 the stigma, and in all cases they bend towards it. When the 

 pollen is shed, the style elongates and lifts the stigma a little. 

 Then the corolla begins to fade and the anthers recede from 

 the stigma. Every gradation was found in the various types 

 between the condition in which the stamens were above the 

 stigma throughout, rendering cross-pollination practically im- 

 possible, and the other extreme case in which all the stamens 

 are so much shorter than the style that self-pollination is fidy 

 possible by insects or by wind shaidng the flowers. Many small 

 bees were noticed visiting the fiowers, and some small flies, 

 covered with pollen, were observed inside the corolla tubes. 

 The arrangements for pollination in the various types can be 

 divided into the following three classes (Plate II) : — 



CIas,s /. — Sfaiiicns nriich hnxjcr f/idii. fhc sti/Ic. 



In this class the style is decidedly shorter than the stamens, 

 so that the four longest stamens bend over the stigma, and in an 

 open flower the stigma is not visible, being always covered by the 

 stamens. In such flowers cross-pollination is almost impossible, 

 and this condition was (bund in types V and XV. 



Class II. — Stamens about the same Unujth as the style. 



This class includes the various conditions intermediate 

 between classes I and III, and comprises the majority of the types. 

 The stamens may be a very little longer than the style, so that 

 about half the anther projects above the stigma and the latter in 

 the opened flower is surrounded by the burst anthers, but is not 

 obscured by them as in class I. This condition is found in t^^pes 

 XIII and XIV. In other cases the tip of the anther only may 

 project above the stigma and the pollen is deposited round its edge 



