112 TRANSACTIONS OF THE 



Of those plants that are fertilised by the wind, the best example 

 I can give is what is found in the various grasses (Fig. 4). The 

 pollen in them is very loose and easily wafted about by the wind, 

 so that when they grow together, as in a field of corn, there is 

 every chance of the plant being fertilised. The pistils are more or 

 less feathery (Fig. 6), and present a very large surface, so that 

 they will be sure to catch some of the pollen as it flies about. In 

 the alder, hazel, and willows we have very good examples of wind- 

 fertilised plants. In these the stamens are in one set of flowers 

 and the pistils are in another, either on the same plant, as in the 

 alder and hazel, or on diflferent plants, as in some willows. Now, 

 in these plants, as the leaves might interfere with the application 

 of pollen to the stigma, it is found that they are not developed 

 till after the plant has been fertilised. 



Let us take the case of the hazel, in which the stamens are 

 matured first. 



Here, as in grasses, we have loose pollen, easily carried about by 

 the wind, and if the trees are in close proximity, there is every 

 reason to believe that pollen will be blown from one plant to 

 another. Whether or not, shortly after the stamens («) are 

 matured, the female flowers (b) begin to send out their pistils, 

 and the slightest breath of wind is sufficient to send a shower of 

 pollen about the female flower. 



Again, to take the case of the willows. Most of them are fei-til- 

 ised in the same manner as the hazel ; but there are some willows, 

 e.g., Salix pentandra, which cannot be fertilised in this way. 

 Curiously enough, here we have the leaves developed before either 

 the male or female flowers ; and as the pollen is not loose, as in 

 other willows, and besides, the male and female flowers are on 

 different plants, fertilisation would be absolutely impossible with- 

 oixt the agency of insects. Consequently we have the development 

 of a kind of nectar. The whole plant has a sweet smell ; hence 

 the name of Sweet-bay "Willow. And in spring, when standing 

 under one of these trees, we can. hear the perpetual hum of the 

 bees as they fly from flower to flower. In another group of plants, 

 fertilised by the agency of the wind, viz., the great group of cone- 

 bearing plants, Goniferce, we have the evei-green leaves very 

 narrow, and besides, we have a peculiar structure developed in 

 connection with the pollen grain, which serves in a great measure 

 to enable the pollen to reach the female flower. 



