536 OUR WOODLAND TREES. 
its popular name, although it should be more 
correctly described as the Scotch Pine. 
Here it may be useful to point out the principal 
botanical distinctions which have suggested dif- 
ferent generic names for the Conifers represented 
in the descriptions in this volume. The genus 
Pinus, of which we describe, in addition to the 
subject of this chapter, Pinaster (or Cluster Pine) 
and Pinea (or Stone Pine), includes Conifers 
which have their male flowers in grouped or clus- 
tered catkins, their pollen enclosed in two cells, 
their carpels—answering to the scales of the 
cones—thickened at the tips, and their leaves 
mounted in sheaths, containing two or more. 
The genus Alies, of which we describe the species 
Hxcelsa (or Spruce Fir), possesses the same cha- 
racters as those of Pinus, with the exception that 
the cones droop, and the leaves are solitary and 
not grouped in sheaths. The genus Picea, of 
which we describe the species Pectinata (or 
Silver Fir), is distinguished from Pinus in the 
carpels not being thickened at the tips, from 
Abies in having the cones erect, and from both 
these genera in having the leaves arranged in two 
