THE CONIFEROUS FORESTS 235 



is impossible, without entering on a lengthy and 

 technical botanical discussion, to indicate precisely 

 in what these differences consist. It may suffice to 

 say that the Conifers do not bear flowers. The 

 organs which produce the pollen and the ovules, 

 which when fertilised become seeds, are borne on 

 special, complicated fertile shoots known as cones. 

 These produce either pollen or ovules, but never 

 both, and are thus spoken of as male or female 

 cones. Both types may occur on the same or on 

 different trees, according to the genus. All the 

 Coniferai are wind fertilised. 



At a height of about 5,000 feet (which we here 

 regard as the lower limit of the Alpine zone), the 

 Beech, so characteristic of the Subalpinc region, is, as a 

 rule, entirely replaced by the Spruce and Larch. 

 Forests in which these trees figure largely are of 

 course common also in the Lowland and Subalpinc 

 zones, but they are there associated with other trees, 

 not found in Alpine habitats. 



The Coniferous forests extend upwards to a height 

 which depends on a great variety of circumstances. 

 Often the upward limit is as low as 6,000 feet, 

 but in the Zermatt region it is as high as 7,600 feet. 

 No general rule can be laid down, for the upper 

 frontier depends on various local conditions such as 

 the height of the floors of the neighbouring Alpine 

 valleys, the nearness or remoteness of the snow-line, 

 and the situation, or aspect of the jmrticular district. 



The best way to view the vertical distribution of 



