396 Successful Method of managing Aquatic and Bog Plants. 



which reason, in basins of this decription, let them be ever 

 so much exposed to the sun, Conferva are rarely produced, 

 provided the height of the jet is in due proportion to the 

 diameter of the basin.* 



For these reasons ponds are preferred, which are either lined 

 to a certain depth with a thick coat of clay, or made water- 

 tight by means of masonry or brick-work ; they are then 

 filled with mould, and the plants set in them. But such 

 ponds, while they take up far too much room, which might 

 be better employed, do not completely answer their object. 

 For as plants are cultivated in a botanic garden solely for 

 the purpose of being studied with the greater ease, the edges 

 of these ponds only can be planted, the centre part being- 

 out of reach ; this space consequently is lost to the garden. 

 If the pond be freely exposed to the sun, without any consi- 

 derable current in the water, it may be filled with different 

 species of green Conferva?, which will spread to the edges of 

 the pond, render the plants that grow there foul, and if they 

 happen to be of a tender nature, even destroy them. 



It might possibly be contrived that the ponds being made 

 small, the centre might be reached, but another, inconveni- 

 ence remains unavoidable, arising from the plants themselves. 

 Almost all water plants have creeping roots, in some (as 

 Menyanthes trifoliata ) the creeping stems often change into 

 roots ; it therefore happens that the plants placed in a pond 

 soon grow confusedly and wildly through one another ; the 

 small, the tender, or, if I may say so, the modestly growing 



* These artificial fountains, or water-works, to which the author alludes, are 

 in modern times not much seen in Engalnd, but they still form a great orna- 

 ment to the gardens on the Continent. 



