HISTORY OF PLANTS.« 399 
from them, and that 'they really were different spe- 
cies, And why should nature not produce, under 
different latitudes and longitudes, species which are 
very like each other! 
§ 363; 
In all climates a singular diversity in plants may 
be observed, viz. that some are sociable, as it were, 
others remain always solitary ; or some are never 
found but in great numbers crowded together, 
others are only singly scattered over the ground, 
and grow quite solitary. he reason of this sin- 
gular phenomenon seems simply to be, that the 
seeds of such plants are either too heavy to be car- 
ried off by the wind, or that being light they are 
carried high up by a gentle breeze, and easily fall; 
or that the elasticity of their fruit capsule does not 
scatter them sufficiently. ‘The roots of some plants 
e likewise luxuriant, and make plants grow in 
numbers together. 
Vhose gregarious plants often occupy great tracts 
of land.. Common heath, (Erica sates is often 
spread many miles. The myrtle berry, ( Vaccinium 
myrtillus), the strawberry, (Fragaria vesea), some 
species of Pyrola, some Junci, and some trees be- 
long to them. Solitary plants are, ‘Purritis ¢/abra, 
Anthericum Liliago, Lychnis ee. and others. In 
very populous Sau man himself changes the 
face of the country, by planting forests, and placing 
plants closer together, which originally were more so- 
itary. The difference, therefore, between solitary and 
sociable or gregarious plants only strikes him in such 
9 
ad as .- 
: 1 
