318 
considered not only highly proper, but indispensably necessary. As this 
practice has therefore, from long and extensive experience, been proved 
beneficial, it ought to be particularly attended to by the proprietors and 
farmers of all ranks, in every part of the island where improvements have 
only been recently or but partially introduced. 
In the year 1^91 some seeds of Zmania aquatica were procured from 
Canada, and sown in a pond at Spring Grove, near Hounslow: it grew, and 
produced strong plants, which ripened their seeds; those seeds vegetated in 
the succeeding spring; but the plants they produced were weak, slender, 
not half so tall as those of the first generation, and grew in the shallowest 
water only, the seeds of these plants produced others the next year sensibly 
stronger than their parents of the second year. 
In this manner the plants proceeded, springing up every year from the 
seeds of the preceding one, every year becoming visibly stronger and larger, 
and rising from deeper parts of the pond, till the last year, 1/84, when 
several of the plants were six feet in height, and the whole pond was in 
every part covered with them as thick as wheat grows on a well managed 
field. 
Here we have an experiment which proves, that an annual plant, scarce 
able to endure the ungenial summer of England, has become, in fourteen 
generations , as strong and as vigorous as our indigenous plants are, and as 
perfect in all its parts as in its native climate. 
Some of our most common flowering shrubs have been long introduced 
into the gardens; the Bay-tree has been cultivated more than two centuries; 
it is mentioned by Tusser, in the list of garden plants inserted in his book, 
called Five Hundred Points of good Husbandry, printed in 1 5^3> 
The Laurel was introduced by Master Cole, a merchant, living at 
Hampstead, some years before 1629 , when Parkinson published his Paradisus 
Terrestris, and at that time we had in our gardens Oranges , Myrtles of three 
sorts, the Laurustinus , Cypress , Phillyrea, Alaternus , Arbutus ; a Cactus brought 
from Bermudas, and the Passion Flower , which last had flowered here, and 
showed a remarkable particularity, by rising from the ground near a month 
sooner if a seedling plant, than if it grew from roots brought from Virginia 
All these were at that time rather tender plants; Master Cole cast a 
blanket over the top of the Laurel , in frosty weather, to protect it; but 
though nearly two centuries have since elapsed, not one of them will yet 
bear with certainty our winter frosts. 
