III. CROPS WITH OPEN FLOWERS. 



1. Tobacco. 



Two species of tobacco are cultivated in India, namely, Nico- 

 tiana tabacum, L., and N. rustica, L. The cultivated Indian types 

 of both of these species have been described by us in previous 

 papers' and, in addition, the methods of pollination and the fre- 

 quency of natural cross-fertihzation have been studied. 



In the flowers of N. rustica the anthers always burst in the 

 bud before the corolla opens and 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 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 gradatfou 

 was found in the various types between the condition in which 

 the stamens were above the stigma throughout, rendering cross- 

 pollination practically impossible, and the other extreme case 

 in which all the stamens are so much shorter than the style that 

 self-pollination is only possible by insects or by wind shaking 

 the flowers. Many small bees were noticed visiting the flowers, 

 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 IV) : — 



Class I. Stamens much longer than the style. 

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

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



1 Howanl and Howanl, Meinolrg of the Departmetit of Agricvltuve in India (Botanical 

 Series), Vol. Ill, Nos. 1 ic 2, 1910. 



