III.] 



POLYGALACE^. 



63 



watched some large clumps of heartsease, many times 

 daily, for a fortnight, before I saw a humble-bee at 

 work. During another summer I did the same, and 

 then one day, as well as on two succeeding days, I 

 saw a dark-coloured humble-bee visiting almost every 

 flower in several clumps ; and after a few days almost 

 all the flowers suddenly withered, and produced fine 

 capsules. A certain state of the atmosphere seems to 

 be necessary for the secretion of nectar, and as soon 



Fig. 59. — Polygala vulgaris, 



as this occurs, it is perceived by various insects, I pre- 

 sume by the odour emitted by the flowers, and these 

 are immediately visited." 



POLYGALACEyE, 



This order contains, according to Bentham, but one 

 British species, which, however, is very common, the 



