PINUS. REPRODUCTIVE ORGANS. 155 



scale-leaves, in the axils of which are lateral axes 



easily seen on removing the scales. Of these lateral 

 axes 



(a.) Those nearest the apex of the bud develop as 

 lateral foliage-shoots (cf. ordinary vegetative axis). 



(b.) Below these, a number bear, in place of the 

 two foliage leaves, numerous Staminal leaves (these 

 axes are Flowers). 



Comparing the male inflorescence with the ordinary 

 vegetative axis, the main difference lies in the mode of 

 development of the lateral axes. In autumn the male 

 inflorescences of the preceding summer can only be 

 distinguished from the purely vegetative axis, by the 

 absence of the lateral foliage-shoots from the lower 

 parts of them. 



B. Separate a single male flower, and cut it longitu- 

 dinally in a median plane : it will be found to consist of 



1. An Axis, which bears. 



2. A number of Staminal leaves. 



Detach some of these staminal leaves with a needle : 

 each consists of 



(<z.) A short stalk, or Filament, which bears at its 

 apex 



(6.) An expanded Anther, with two swellings (Pol- 

 len-sacs, or Microsporangia) on the lower surface. 



0. Cut longitudinal sections of the male flower in 

 which the pollen is not yet ripe, and mount in glycerine : 

 examine with low power. Note the arrangement of the 

 parts as above described. In the pollen-sacs note the 

 Pollen-grains in situ (Microspores). 



The pollen is ripe about the middle of June, and material 

 ghoul d be collected and preserved in alcohol at such time as to 



