HYDROCHARIDACE^ 17 T 



Pinus Pinaster, Soland. A native of Southern Europe 

 introduced into England in the sixteenth century, and 

 now abundantly naturalised near Bournemouth and 

 in one or two other places. 



[Pinus sylvestris, L. An undoubted native of Great 

 Britain in recent geological times, probably forming 

 large forests. Whether any of the Scotch pines growing 

 now are descended from the wild stock must always 

 remain doubtful, but, as it is undoubtedly native in 

 other parts of Northern Europe, it may be allowed the 

 benefit of the doubt and a place among the rarer natives 

 of Britain. The tree has been abundantly planted in 

 all parts of the islands.] 



HYDROCHARIDACE^. 



Aponogeton distachyon, Thunb. A South African 

 aquatic, often grown in England in ornamental ponds, 

 whence it occasionally escapes into wild-looking 

 situations. 



Elodea canadensis, Michx. Native of North America. 

 It seems to have been first observed between the years 

 1842 and 1847 near Bewick, near Market Harborough^ 

 and in Cambridge. From these centres, and perhaps 

 from others unrecorded, it spread with extraordinary 

 rapidity over the whole of Britain. It is now showing 

 signs of decrease, perhaps in consequence of its long 

 dependence (in the absence of the male plant) upon 

 vegetative reproduction. 



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