108 THE FLORA OF HARROW AND ITS VICINITY, [ApHl, 



some objects of interest for the student of Natural History. There 

 are^ in fact^ many favoured spots which possess at the same time 

 a rare and varied Flora. In some other places, the rarity of the 

 native wild plants amply compensates for the want of variety, 

 while in others the native plants are neither rare nor varied. 

 Under this last class we are unwillingly compelled to place the 

 neighbourhood of Harrow. We are thankful to add that a re- 

 stricted Flora is no sign of natural sterility, and may adduce the 

 fertile fields around us as evidence of the fact. While the Flora 

 of Harrow is necessarily limited by the nearly uniform character 

 of its soil, there are accidental circiamstances which restrict it 

 still more. The greater part of the land being under grass pre- 

 vents the growth of many plants which under other circumstances 

 would flourish in the soil ; and there is no reason to doubt that 

 many plants which fifty years ago belonged to the local Flora, have 

 been exterminated by grass farming. There have, however, been 

 sources of gain, as well as of loss. The cattle- pools in the pasture- 

 fields, and, above all, the canal, have introduced many aquatic and 

 semi-aquatic plants, which could not otherwise have appeared in 

 a Flora of this district. The most remarkable of these additions 

 is the Anacharis Alsinastrwn, Bab., a Canadian plant unknown 

 to British botany before August, 1 842, when it was found growing 

 quasi-spontaneously in a small lake in Berwickshire, Since its 

 first appearance in that spot, it has spread itself over a large 

 portion of the canals of Great Britain, and is now to be found in 

 many of our English rivers. Its appearance in the canal is not 

 so very strange ; but that this intriguing foreigner should (how 

 we cannot say) have ascended the hill on which our venerable 

 church stands, and have found for a time a local habitation in the 

 pool in the church fields, almost surpasses belief. The fact is 

 nevertheless true, although we cannot now convince any one of 

 its truth by the "seeing is believing" argument; as our local 

 authorities, in levelling the ground for the new churchyard, have 

 buried the intruders under some twelve feet of clay. We feel 

 assured that its wonderful powers of self-propagation have been 

 put a stop to in one locality at least. A few other plants have 

 found a congenial soil on the top, or at the foot, of old walls ; as 

 on the garden wall at the Grove, and in other places. 



The number of Flowering Plants and Fern allies, so far as at 

 present ascertained and catalogued below, amount to 385 species 



