It is probable that a regular supply of moisture, 
in accordance with the requirements of the plant, 
would altogether prevent their formation. We know 
that some species of grass, which are strictly fibrous- 
rooted, particularly the phleum pratense, produce 
tubers, in situations where they are exposed to the 
occasional want of fluids necessary for their luxuri- 
ant or healthy increase. 
When suffering under such privations, it may be 
conceived that the stems and roots of a plant become 
less flexible; and its vessels being constringed by 
drought, would be incapable,when subsequently sup- 
plied with a due portion of fluids, of ready and free 
dilatation. In this state, the fluids collected by the 
extremities of the roots may be prevented, by the 
rigidity of those parts near the surface of the earth, 
from freely ascending. At this point an accumula- 
tion of its juices occurs, and somewhat analagous to 
the aneurism of an artery, a tuber is produced. These 
tubers, gradually increasing, subsequently become 
reservoirs, to meet any deficiency of supply that may 
casually occur. Thus we see infinite wisdom making 
the very existence of a want the means of its remedy. 
A proper distinction must be observed between 
such tubers as are mere reservoirs of unprepared 
fluids, and those which are depositories of elaborated 
Juices from the plant, in which the vitality of a future 
individual of its species exists. 
The herbage of the Phlomis tuberosa, having a 
bold, and rather rough, appearance, renders it most 
suitable to the foreground of the shrubbery. Our 
plant grows freely in a red sandy soil, and an ex- 
posed situation. 
Hort. Kew. 2, v. 3, 408. 
