HTDROCHAKIDACE^. 83 



tlon from tlie American continent. Almost at the same time otLor observers disco- 

 vered the plant in various situations, having had their attention drawn to it by Mr. 

 Babington's paper. Dr. Johnston found it in two places in the Whitadder River. 

 Mr. James Mitchel writes that in the Lene, a tributary of the Trent, near Nottingham, 

 it was "growing in great profusion for about a quarter of a mile in extent." In 

 November of the same year it was found in Northamptonshire, in the Watford Locks, 

 by Jlr. Ku-k, in great abundance. He considered it to be an introduced plant at that 

 time, but afterwards changed his views, from its simultaneous discovery in so many 

 other localities. All his specimens were female, and growing in such dense masses 

 that it was with difficulty good-sized specimens could be detached, from its extreme 

 brittleness. Mr. Kirk was informed by the lock-man that the plant was quite as 

 abundant when he first came to the lock five years before, although the reservoir had 

 been cleaned out once or twice during that period. The lock-man further stated that 

 he had formerly resided at Foxton Locks, and that the reservoirs there were full of it 

 " more than twenty years back ; " also that it had been plentiful in the Market Har- 

 borough Canal during the whole of that period. A short time after this conversation 

 took place two labourers belonging to the lock came up, and both of them confirmed 

 the statement of its being plentiful in the Market Harborough Canal, and one of them 

 added that the " Welford Branch," a narrow canal comparatively little used, was so 

 full of it that " the passage of boats was impeded, and the canal necessitated to be 

 cleared out once or twice a year, and that it had been so for many years." Mr. 

 Marshall believes there was some mistake here, and it is well to remember that the 

 evidence of persons unaccustomed to observe is of very small value in natural pheno- 

 mena. The plant seen by the lock-men may have been altogether a different species, 

 but that it was a fast-growing water- weed would be enough to account for their con- 

 fusion. Scientific data are founded on the observations of competent witnesses 

 only. In August 1849, the Anacharis was found in Derbyshire and Staflbrdshire 

 by Mr. Edwin Brown, growing in profusion in the Trent. He was convinced that 

 the plant was new to that locality. AU the plants were female. In Christmas 

 1850, it was found by Mr. Kirk in Warwickshire, near Rugby, in the greatest abun- 

 dance; and in July 1851, by the same gentleman in the Oxford Canal, near Wyken 

 CoUiery. The Rev. W. Hind, wi-iting from Burton-on-Trent in July 1851, describes 

 the plant as having greatly increased in eighteen months, and says " it bids fair to 

 block up one of the two streams into which the Trent here divides." In 1851 Jlr. 

 Marshall and others noticed the plant in the river between Ely and Cambridge, but 

 not in large quantities. Since then it has increased so rapidly and wonderfully that it 

 has become the greatest source of annoyance to aU watermen, and navigation seems 

 almost to be arrested by it. Sluice-keepers complain that masses of it get into the 

 pen, and retard the operation of letting boats through very greatly. The railway 

 dock at Ely became so choked with it recently that several tons of it had to be hfted 

 out. Rowers complain sadly of it, and the University oars find it so prejudicial to 

 their progress, that, giving their Professor of Botany the credit or blame of intro- 

 ducing it into their river, they called it Bahiiigtonia pestifera* Besides the annoyance 

 that this weed is to boatmen and fishermen, the drainage is considerably impeded by 

 it, and it is therefore a question of great importance as to how its rapid increase can 

 be arrested. The arguments for the origin of this plant in our rivers, or in those of 



Professor Babington did not introduce it at Cambridge. See p. 84, Hue 24, et 

 seri. — Ed. 



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