THE PRINCIPLES OP BOTANY. 
101 
this account to be understood that they differ in growth from 
other Exogens; on the contrary, they are essentially the same, 
deviating in no respect from the plan on which Exogenous 
plants increase, but having a kind of tissue peculiar to 
themselves.—‘ Vegetable Kingdom,’p. 221. The nahecl seeds 
then upon which the class is founded is the grand distinctive 
element, but no less so is the general style of the typical 
orders of which the class is formed. 
The Orders of Gym no gens. 
CrcADACEiE—Stem simple, continuous; leaves, parallel-veined, pin¬ 
nate ; scales of the cone, antheriferous. 
Pinacea:—S tem repeatedly branched, continuous; leaves simple, 
acerose; females in cones. 
Taxacea—S tem repeatedly branched, continuous; leaves, simple, 
often fork-veined ; females solitary. 
Gnetaceai—S tem repeatedly branched; continuous; leaves simple, 
net veined. 
Two of these orders we shall now especially refer to, 
namely, the Pines and Yews, which, though having so much 
in common in their arborescent growth, are yet well distin¬ 
guished by their fruits. 
The Pinacece include some of the grandest trees in the 
world, on which account great attention has been paid to 
their cultivation, and ee Pinetums ,” or plantations especially 
devoted to collections of the Pine or Fir tribes, are not at all 
uncommon. 
We have, however, a very small native list connected with 
the class, and the order Pinacese is indeed represented by only 
two species, the Pinus sylvestris , commonly known as the 
Scotch fir, and a representative of a second section in the 
Juniperis communis , the common Juniper shrub of some of 
our dry calcareous hills. 
We have for years commonly grown for residential pur¬ 
poses, as well as for profit, the Norway spruce, the larch, 
and the cedar of Lebanon, and more recently spruce, pines, 
and deodars of endless species and varieties. 
Both the Scotch and Norway firs grow sporadically, that 
is, increase naturally from seed, as has been noted by Sir W. 
Hooker in Scotland, where, speaking of the first, ff it consti¬ 
tutes vast natural forests ; ” and Dr. Blomfield remarks that 
“ P. sylvestris and P. pinaster , though not aborigines, are 
becoming established by spontaneous dissemination over the 
vast moorlands and bog tracts of West Hants and Dorset, 
which they seem disposed to convert into pine woods similar 
to those in the Highlands of Scotland, the Landes of Bor¬ 
deaux, or the pine barrens of North America.” 
