152 Postelsia 
or may be crowded together into fascicles borne 
on special dwarf branches. 
The Abzetinee are widly distributed through 
the boreal regions, the north temperate zone, 
and the adjacent mountainous parts of the 
tropics. From five to nine genera and about 
130 species are recognized. Almost two-thirds 
of the species, representing all but one of the 
genera, inhabit the Pacific slopes of North 
America and Asia. 
The following is a synopsis of the North 
American genera of A bietinee. 
A. Shoots of two sorts, long and dwarf; leaves 
of dwarf shoots fascicled. 
a. Only scale-leaves borne by the long shoots; 
fohage leaves persistent, in fascicles of 
2-5 (rarely 1 or 6). Cones ripening the 
second year; cone-scales more or less 
thickened at apex. Pinus 
b. Folage leaves deciduous, borne singly on 
the long shoots; those of the dwarf shoots 
forming large fascicles. Cones ripening 
in one season; cone-scales thin. Larix 
