24 College of Forestry 
phyte.t I have in mind such growth forms as needle-leaved 
evergreen tree, broad-leaved evergreen tree (scarcely repre- 
sented however, in our vegetation) broad-leaved deciduous 
tree, evergreen shrubs (e. g. certain heaths) and deciduous 
shrubs; herbaceous annuals, creeping, sprawling, climbing 
and twining plants; plants perennial by underground stems 
(rhizomes, bulbs, tubers) or food storage or woody roots ; 
grass like, weed like and rushlike grow ths; tussock formers 
hike Carex stricta, royal fern, cinnamon fern: sod forming 
grasses and sedges; mat forming cat-tail and sedges; sub- 
merged pondweeds, floating leaved aquatics and so on. 
Looking over the world at large the range of growth forms 
is vastly widened beyond those represented in our vegetation. 
It is obvious that there is a certain relation existing between 
erowth forms and environment. Note especially the corre- 
lation between desert environment and desert growth forms, 
between water habitat and aquatic plants. In reality this is 
no more marked than is the correlation between our local 
growth forms and the alternating summer—winter features 
of this environment. Now the compelling idea in this connec- 
tion is that here, also, we have a state of things arrived at by 
a process of development — of evolution and adaptation, if 
you please. We cannot ignore the fundamental characteris- 
tics of living plants — their plastic nature, the energy which 
drives them into all the earth in the face of all diversity of 
environment, the response or outcome of this prolonged racial] 
experience in the various growth forms or adaptation forms 
which we are here considering. In a subsequent paragraph 
reviewing the geological history of vegetation, this differen- 
tiation of growth forms will be found to be strikingly cor- 
related with the appearance on the earth of angiosperms with 
their unique floral structures and with the greatly diversified 
features of the continents which are said to have come about 
1 That is, a plant differentiated into the well known regions of root, 
stem and leaf members. 
2No attempt is here made to give a classification of growth forms on 
any scientific basis. As to such classification see Drude, Oscar, Die 
Okologie der Pflanzen, 1913, pp. 31-112. 
