Postelsia 205 
A Key to the Genera of Conifers found in 
northwestern North America, based upon their 
*k 
foliage. 
ieolace, of linear or acicular leaves, ae: 
jmeedless 
A. Foliage leaves, or some of them, borne in 
fascicles on dwarf branches. 
a. Leaves not deciduous, all the foliage 
leaves borne in fascicles of 2-5. 
Pinus p. 153- 
b. Leaves deciduous, arranged spirally 
upon the long shoots of the sea- 
son’s growth and in crowded fas- 
occur west of the Cascade Mountains, The other is the species described 
above. These two species have been badly confused by collectors. 
It does not appear entirely certain which of these is Hooker’s /uz- 
tperus occidentalis, which was founded by him upon two non-fruit- 
ing specimens collected by by Douglas “from the higher parts of 
the Columbia, at the base of the Rocky Mountains.” Hooker states 
that his species has four-ranked leaves, but his note after the descrip- 
tion indicates that he had the Idaho-California species, especially as 
he states that there is a large gland on each leaf constantly exuding 
a transparent resin which concretes in drops upon the foliage,—a 
character which is often very prominent in that species, whereas the 
leaf gland of Juniperus scopulorum Sargent, is small and not resin- 
secreting. 
*This key is based upon the foliage of the mature plants. Dur- 
ing the first few years of the plant’s growth its foliage often. differs 
entirely from the mature form. Noattempt has been made to in- 
clude these seedling characters. 
