[Enclosure]

Extract from Wells’ Annual of Scientific Discovery. 1854. Page 334. Trübner & Co, London. “Curious Fresh Water Plant.

A recent number of the Edinburgh Journal contains a description of a new and singular fresh-water plant, which has recently appeared in the inland waters of Gt. Britain, filling her canals, lakes and streams, and threatening, unless a remedy be speedily discovered, to interfere seriously with, perhaps to destroy, all or most of her facilities for inland navigation and drainage.³ This terrible foe is a species of aquatic weed, the first specimen of which was discovered in the year 1842, in the lake of Dunse Castle, Berwickshire, Scotland. The appearance of the little vegetable stranger excited considerable interest among botanists, and the discovery was duly noted in various scientific publications; speciments were sent to a few individuals, and then—it was forgotten. But the plant was of too aspiring a character to live and blush unseen in British waters. In 1847, it was found growing in great abundance, and closely matted together, in the reservoir adjoining the Foxton Locks, on the Canal in Leicestershire. This discovery induced a re-examination of the original plant, when it was found that the long-neglected water-weed had travelled out of the lake, and was making its way down the Whiteadder to join the Tweed. In the same season it was found in great profusion in a tributary of the Trent, in Nottinghamshire, and it was also discovered to exist in “dense masses, and great abundance” in the Watford Locks, Northamptonshire. In 1849, it appeared in Derbyshire and Staffordshire, “forming very large submerged masses, of a striking appearance,” in the Trent and adjoining canals. In 1850, it was found near Rugby, in Warwickshire; and in 1851, it was discovered in the rivers Ouse and Cam, near Cambridge.

The botanical interest which was at first excited by the discovery of large quantities of this new plant in various districts, at nearly the same time, soon gave place to a feeling of serious alarm prompted by the injurious effects of its unparalleled increase. A year after it was first noticed in the Cam, the stream near the Colleges was so blocked that extra horses were required to draw barges through the vegetable mass. A year after its appearance at Ely, the railway dock became so choked with the weed that boats could not enter until several tons of it had been removed. In many places fishermen were obliged to discontinue setting long lines, or using nets, because the weed either carried them away or stripped them of the fish. It is evident that this plant, styled by Mr. Babington, of Cambridge, the anacharis alsinastrum, cannot a great while have been a native of Gt. Britain.⁴

If so, its remarkable prolific powers would long since have brought it into notice. And it is a noteworthy fact that the anacharis is dioecious,—that is, the male and female flowers grow on separate individuals,—and all the plants known to exist in England are females. This fact affords an almost positive proof that only one stem or seed of a female plant was the progenitor of all the anacharis in Gt. Britain; and this seed was possibly introduced from Canada in the crevice of some one of the many logs which are annually conveyed across the ocean to England, and of which so many have been used in the great rail-road works at or about Rugby. It is thought that in the clear, swift-flowing rivers of America, the weed would not form the immense masses which characterise its growth in the sluggish and—as they contain a greater amount of inorganic animal and vegetable matter,—more nourishing waters of the English rivers and canals. But our readers will inquire how—as only the female anacharis has been discovered in England, and it is therefore unable to propagate seed in that country,—how it contrives to extend itself so rapidly and widely, and wherein are its prolific powers vested. These questions are easily answered; its leaves, which grow in threes, around a slender stem, are studded with minute teeth which cause them to cling to every object with which they come in contact, and the stem is so very brittle that whenever the plant is disturbed pieces are broken off; and as every fragment of the stem is capable of becoming an independent plant, producing roots and leaves, and extending itself indefinitely in every direction, it is evident that the anacharis must be in an almost continual state of reproduction. All the localities in which this singular plant seemed to appear almost simultaneously, are reducible to two,—Dunse Lake, in Berwickshire; and the Foxton Locks, in Leicestershire. It probably originated in the Foxton Locks, and was afterward introduced into the former place. The Foxton Locks are in direct communication with nearly all the English localities of the plant, and a single sprig of the anacharis would in a very short time inoculate any connected water-system, from one end to the other. The plant was introduced by scientific men into the Cam, and other places, originally for experimental purposes, and is of such a nature that, clinging to the bottoms of vessels or boats, it might easily inoculate other streams and waters.

In the case of the Cam, in the short space of four years, it multiplied so, from a single stem, as to impede both navigation and drainage. It has become a great and growing evil; and the attention of scientific men— of practical men— is loudly demanded to the subject of its extinction.”