42 Flowers and their Unbidden Guests. 



specimen possessed eight of the larger basins, one above 

 the other, on the main stem, and besides these a still 

 greater number of smaller and shallower basins on the 

 secondary stems, the quantity of water retained in a 

 single plant may be reckoned at a litre and a half On 

 the fourth and fifth day there was no perceptible 

 diminution to be noticed in the basins, although still 

 no rain had fallen. This maintenance of level can only 

 be explained by supposing that the small quantity of 

 water, which daily evaporated from the comparatively 

 deep basins, was replaced by the dew of the following \ 

 morning ; this dew being deposited on the broad sur- 

 faces of the leaves, and, owing to the slanting position 

 of these, much of it trickling down into the contiguous 

 basins. To this plant again, with its abundant nectar 

 no other insects are welcome than such as fly, and 

 minister to allogamy. Those that creep and would 

 carry off the nectar without profit to the plant, nay 

 even to its disadvantage, are unwelcome, and are kept 

 aloof by the internodes of the stem, over which they 

 must crawl in order to reach the flowers, standing out 

 from the water in the basins like posts out of a pond.^ 



^ [Mr. Francia Darwin (Qiuxrt. Jown. of Microsc. Sc. xvii. 269), 

 has shown reasons for suspecting that the ' ' cups " of the teasel 

 serve another purpose beside the protective one aacrjbed to them 

 by Kemer. He believes that they serve as traps, in which insects 

 are caught, and in which they are dissolved by the contained fluid, 

 so as to serve as food to the plants. He points out the curious fact 

 that " Id the last century Erasmus Darwin should have remarked 

 on the protective function of the ' bason ' formed by the connate 



