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A remarkable plant has recently made its appearance in 
the rivers Ouse and Cam, and already abounds to such a 
degree, as not only to impede navigation, but what is of far 
more importance in this fen country, threatens to injure our 

It occurs in dense tangled submerged masses of consider- 
able extent, and is so heavy, that when cut, (instead of rising 
to the surface and floating down to sea, like other weeds) 
it sinks to the bottom. It is this property which is likely 
to make it injurious to drainage. The intruder is so unlike 
any other watt v [\ nt, tl ;it i* in \ be at once recognized by 
its leaves growing in threes, round a slender stringy stem. 
The watermen on the river have already named it " Water 
Thyme," from a faint general resemblance which it bears to 
that plant. 

That it is neto to our rivers here, is certain ; watermen and 
fishermen pronounce it to be, (as I heard one of them call it 
the oiiu.r day), " a furreigner." 

Who the stranger is, whence lie came, and how he got 
here, are questions of consideraMc seimtfii; interest; but hy 
what means he is to be got rid of, is the practical question. 
With your permission I will discuss these points in another 

Yours obediently, 
Ely, August 11, 1852. W. MARSHALL. 

P.S.— As I am anxious to know how far the plant has 
spread itself through the rivers of the Eastern Counties, if 
any of your readers residing in the Middle Level, or on the 
banks of any of the tributaries of the Ouse, would favour 
me with their experience, I should be greatly obliged. 

No. II. 

I now trouble you with the second part of my communi- 
cation on the subject of this new Water Weed, in which I 
promised to discuss, who the stranger is— whence he came— 
how he got here-and, by what means he is to be got rid of? 

With respect to the first question it is sufficient to say, 
that it is the " Anacharis Alsinastrum" of your eminent 
townsman, Mr. C. C. Babington (to whose accurate labors 
our indigenous botany is so much indebted), who so named 
it in 1848. 

The following is a short account of what we know of the 

It appears that it was first found in this country on the 
3rd August, 1842, by Dr. Geoege Johnston, of Berwick- 
on-Tweed, in the lake of Dunse Castle, in Berwickshire. 
Ihe lake is situated upon a tributary of the Whiteadder 
Kiver, which flows into the Tweed. Specimens were sent 
at the time to Mr. Babington ; but the discovery was lost 

sight of, and the interest in it died away until the Autumn 
of 1847, when it was again discovered by Miss Kirbv, of 
Lubbenham Lodge, in reservoirs adjoining the Foxton Locks, 
on the Canal near Market Harborough, in Leicestershire. 
The plants were all females, and were found in considerable 
abundance, growing " closely matted together." Miss Kirby 
had not observed it there before, and the reservoirs had been 
cleaned out two years previously. 

Miss Kikby's re-discovery awakened the attention of 
Botanists to the subject, and Mr. Babington published a 
description of the plant in the " Annals of Natural History," 
for February, 1848. Dr. Johnston, the first discoverer, on 
reading Mr. Babington's account, at once recognized it as 
the plant he had found in the Loch of Dunse Castle, and in 
the following Autumn found the plant in two stations in the 
Whiteadder River. 

The same season, but later, it was found by Mr. James 
Mitchel, in Nottinghamshire, in the Lene, (a tributary of 
the Trent) near Nottingham, " 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 Mr. Kirk, " very abundant." The 
Watford Locks are on the same line of Canal as the Foxton 
reservoirs. Mr. Kirk observed that when water was drawn 
from either of the Locks, the force of the current detached 
small sprigs of the Anacharis, which were carried into the 
body of the Canal. Mr. Kirk considered it to be an intro- 
duced plant. His plants were also all females. Subsequently, 
Mr. Kirk changed his views, and regarded the plant, « from 
its simultaneous discovery in so many other localities," as a 
true native. He also described it as growing in sucli dense 
masses, that it was with difficulty good sized specimens could 
be detached, owing to its extreme brittlcness. Mr. Kirk 
was informed bv the Lock-man thai the plant was quite as 

abundant when he first came to the Locks, five years before, 
although the reservoirs had been cleaned out once or' twice 
during that period. The Lock-man further stated, that he 
had formerly resided at the 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 belong- 
ing to the Locks came up, and both of them confirmed the 
statement of itd being plentiful in the Market Ilarborough 
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." I apprehend however, there 
must be some mistake here. 

In August, 1849, it was found in Derbyshire and Stafford- 
shire, by Mr. Edwin Brown, growing « in profusion,' 1 in 
the Trent, near Burton-on-Trent, and also in the Canal 
there. Mr. Brown was convinced that the plant was new 
to that locality. He describes it as forming " very large 
submerged masses, of a striking appearance." All the flowers 
were females. In Christmas, 1850, it was found by Mr. Kirk 
in Warwickshire, near Rugby, « in the greatest abundance ;" 
and in July, 1851, by the same gentleman, in the Oxford 
Canal near Wyken Colliery. 

The Rev. W. M. Hind, writing from Burton-on-Trent, in 
July, 1851, describes the plant as occupying a much larger 
portion of the river than when first noticed, eighteen months 
before, and adds: « in fact, it bids fair in a short time to 
block up one of the two streams into which the Trent here 

Last year (1851), the Anacharis was noticed by myself 
and other, in the river at Ely, but not in great quantities. 

This year it has increased so much that the river may be 
said to be full of it ; but I must defer a more particular 
account of its behaviour in the Cam and Ouse till next week, 
when, if space permit, I will dispose of the remaining ques- 
tions of whence it came, how it got here, and by what means 
it is to be got rid of. 

Yours obediently, 
Ely, August 18, 1852. W. MARSHALL. 

No. III. 


Having in my last, traced this plant from its first discovery 
i;i 15. Twu'kshirc in 1842, down to its recent appearance in 
the Cam and Ouse, I propose to devote this letter to a par- 
ticular account of its behaviour in our own rivers, believing 
the chief interest connected with it, to lie in this direction. 

I have already described the Weed as growing in dense 
submerged masses, distinguishable at once from all others 
by its " leaves growing in threes round a slender stringy 
stem ;" and although this brief description is amply suffi- 
cient to identify the troublesome pest, a short further account 
of its appearance and habits may not be uninteresting. The 
colour of the plant is a deep green ; the leaves are about half 
an inch long, by an eighth wide, egg-shaped at the point, 
and beset with minute teeth, which cause them to cling. The 
stems are very brittle, so that whenever the plant is disturbed, 
fragments are broken off. Although, at present, it cannot 
propagate itself by seed, its powers of increase are pro- 
digious, as every fragment is capable of becoming an 
independent plant, producing roots and stems, and extending 
itself indefinitely in every direction. Most of our water 
plants require, in order to their increase, to be rooted in the 
bottom or sides of the river or drain in which they arc 

found ; but this is independent altogether of that condition, 
and actually groics as it travels slowly down the stream, after 
being cut. The specific gravity of it is so nearly that of 
water, that it is more disposed to sink than float, and the cut 
masses may be seen under water, either on or near the 
bottom, rolling over and over like woolpacks, clinging to 
every thing they meet with, and accumulating in great 
quantities at locks and bridges (hugging the piers of the 
latter), and grounding in shoal water. Its mode of growth 
may be best seen in still and narrow waters, (such as the 
stream above the mills at Cambridge), where it seems to 
spring first from the two sides and bottom, meeting at length 
in the middle^ and completely filling up the watercourse,^ 
have seen in some cases, almost to the exclusion of the 

^ ^^ a} a,iiuuDL iu me exclusion 01 tne 

water. Except in very quiet places it is not likely to be 

found in flower. I have, however, found it flowerino- in <rr. 

profusion just below Ely ; but as th« tvW ; B dicetious* ( 

" —V > ""«< »a me piant IS i 

producing male and female flowers on separate 

- v-vu o C/ y«,ute J.I1U1V1U 

re » no fear, as I have before remarked, of its prod 



■is country, all the specimens hitherto found being 

• f ' r? h * here Is littIe ** *<" m 1850, and, perhaps 
m 1 49, lt might have been detected in our rivers, if dih- 
g ntlv sought for, it does not appear to have attracted the 
notice of Watermen and the staff of Feu Oflicials, whose 
duty ,t ,s to cut the weeds in the summer time, till last year, 
f omS T "°' IOed in "Operable quantities all the way 
from Small Bridges down to Bottisham Lock, but not to 

that T Pr ° 3ent CXtent - J ''" e been inf0 ™ rf ^wever, 
th even ast year it was raked out of the river near Water- 

ncltT T" " J ""* fOT — • At the 
-"« tunc ,t needs no longer to be sought for, it may be 

.^::rX:;: :;;:;;::,;;;: ?->r^° 

narrow watercourses, and in the upper portions of the river, 
impeding both navigation and drainage. Perhaps its won- 
derful and rapid increase this year may be owing to the 
excess of wet, and the long continuance of hot weather 
raising the temperature of the water to an unusual degree ; 
but if it should continue to increase in anything like the 
same ratio as it has done, the upper parts of our rivers will 
no longer be able to pass their waters to sea, and the Navi- 
gation Interest may surrender to the Eailways what little 
remains to them of the carrying trade. 

That it is already a source of annoyance to our Watermen 
is evident by the universal complaints which have been made 
of the obstructed state of the River Cam. I am told that the 
river at the backs of the Colleges has been so blocked, that 
extra horses had to be yoked on, before barges could be got 
up to Fosters' Mills. 

Sluicekeepers also complain that masses of it get into the 
pen, and when the slackers are drawn, the openings are 
choked, and the operation of letting boats through is greatly 

The Railway Dock at Ely, became so choked with the 
weed that boats could not enter until several tons of it had 
been lifted out. At Roswell Hill Pits, below Ely, the 
entrance docking was blocked, so that the gault boats could 
not get in till it was removed. (It was here where I found 
it in flower). 

Rowers, too, find it interferes with their amusements ; and 
Swimmers remark, that it clings to them like " scratch wtvd," 
and that if they are overtaken by a lump of it, they are 
likely to be cnta i- 1< d an i dr:i jA by it into deep water.* 

Even the Fishermen complain that they can no longer ply 
their nets so freely as they were wont ; and 1 am informed, 


on good authority, that they have discontinued setting their 
hook-lines, (i. e. lines laid across the river with a series of 
hooka attached), because the " new weed" either carries them 
away bodily, or Strips them both of their baits and fish.* 

Lastly, the Drainage is impeded. Mr. Human, Sen., our 
experienced officer, informs me that although the waters this 
season have been run off at Denver Sluice a foot lower than 
in previous years, the average height of the water in the 
river below Cambridge has been a foot higher than in ordi- 
nary seasons ; and he refers at least half this difference to the 
obstructions occasioned by the presence of the " Anacharis." 

From these facts I apprehend your readers will by this 
time have arrived at the conclusion that a troublesome stran- 
ger has intruded himself among us, uninvited, but, whence 
he came— how he got here— and by what means he is to be got 
rid of—will furnish ample materials for another letter. 
Yours obediently, 
Ely, August 24th, 1852. W. MARSHALL. 

No. IV. 
If you were some fine morning to find that a strange 
person, of foreign aspect had intruded himself into your 
house, I imagine the questions which would most naturally 
occur to your mind under such circumstances would be: 
whence came the fellow— how did he get here— and how am 
I to get rid of him? But as no one is presumed to know 
the faces of all his neighbours, you would wish, doubtless, 
before accosting him as an « impertinent foreigner," to make 
sure he was not some obscure native of one of the back 

Trent, Septan, 

streets of your own town. So in the case of our present 
unwelcome visitor, before one can ask the question — whence 
he came ? we ought to be Hy u a stranger. 

Now, some botanists seem to think that he has all along 
been a native of these islands, lint lias " made himself so 
scarce" as not to have been previously recognized by our 
Botanical Detective Force ;* while others pronounce him an 
nnimstakeable foreigner — greedy and rapacious, " fixin" 
himself in John Bull's rivers for all the world as if he had as 
good a right to occupy them as the aborigines themselves. 
For my own part I have no sort of doubt upon the subject : 
I hold with the watermen that he is a veritable " foreigner," 
although I find that the Rev. Mr. Bloxam, who had visited 
its place of growth, said in 1848, " he could find no reason 
to doubt its being a true native ;" and Mr. Kirk, who first 
regarded it as introduced, afterwards changed his views, and 
concluded it must be indigenous, "from its simultaneous 

ce in so many 

localities. "f Whatever .Mr. Blo 

were for his opinion, Mr. Babington appears to 
have agreed with him at that time. If, however, Mr. Bloxam 
thought so, only because " numbers of other water-plants 
grew in the same locality," the reasoning is very unsatis- 
factory, seeing that any introduced water-plant must necessa- 
rily be found in company with other water-plants. The 
other argument derived from its " simultaneous appearance 
in so many localities," loses much of its force, when the 
numerous localities come to be reduced, as I shall hereafter 
shew, to one, or at most two. I have already stated that the 
plant wasjirst found in 18-12, in the Lock at Dunse Castle. 

Now at first sight one would suppose a quiet Lake in Scot- 
- land beyond the reach of sophistication ; but Dr. Johnston 
informs me that aquatic plants have been introduced into that 
piece of water from the south. Here then we have evidence 
of the probability of the Anacharis being an introduced plant 
at Dunse. Then we learn that, six years after, it was found 
in the Whiteadder, between the Lock at Dunse and the sea; 
and now in August, 1852, Dr. Johnston writes to me thus: 
" As with you, so with us, the weed is altering the character 
of the Whiteadder, and will require before long to be dealt 
with as we have dealt with savages in some places." Its 
second discovery was in the Foxton Locks, situate on the 
Union Canal, which connects Market Harborough with 
Leicester, and the river Welland with the Soar and (through 
the Soar) with the Trent. When therefore it was found in 
the Lcne, near Nottingham, it should be remembered that 
it was in a part of the same water system. Afterwards, it 
was found in the Locks at Welford and Watford, near 
Northampton; but these points are within a very short 
distance of each other, and both are on the same line of canal 
as the Foxton Reservoir. In 1849, it was found in the canal 
near Burton-on-Trent, and in the Trent River; but these 
points, although in two new counties, were all in water com- 
muniration with the previous stations ; and again, .when it was 
found in- Warwickshire, near Eugby, and in the Oxford 
canal, these are within ten or twelve miles of the Watford 
Station, and on the same line of canal. These several Midland 
localities may therefore be regarded virtually as but one, 
because the Anacharis, when once introduced, would, in a 
few years, inoculate any connected water system from one 
end to the other.* 

Indeed, If any one will take the trouble to look at a good 
map of England, it will appear clear that there was hardly 
a spot so well calculated as a centre from which to inoculate 
our English rivers, as Eugby or the Watford Locks, near 
the Crick Eailway Station. From such a point, situate at 
an altitude above the sea of about 350-feet, and very nearly 
at the line of watershed which divides England into the 
River Basins of the Severn on the west ; the Trent on the 
north ; the Ouse on the east ; and the Thames on the south; 
a few detached sprigs travelling different ways, would enter 
the Severn through the Avon via Eugby and Warwick ; the 
Thames, through the Cherwell at Banbury, and thence by 
Oxford ; the Nene, above Northampton ; the Ouse at Buck- 
ingham; the Welland, at Market Harborough; the Trent 
above Burton, by the Anker and Tame; and again, lower 
down at Nottingham by the Soar; and from Nottingham 
the Witham could be reached by the Grantham cana£ and 
from thence by Lincoln, the Drains of North Lincolnshire 
would be impregnated. And then, when the pest had tra- 
velled as far down (on the Trent, for example) as the top of 
the Humber), the numerous vessels ascending the Great 
Valley of 4,000 square miles, drained by the Yorkshire 
Ouse, would carry it up with them, and so inoculate that 
ample river and its numerous tributaries. 

That the plant is only now descending these rivers is evident 
It has appeared in the upper part of the Ouse, and for four 
years has been observed in the Nene; two years ago it 
appeared at Lincoln, but had not then reached the northern 
parts of that country, and in our own river, while it occupies 
the biie of descent from Cambridge to the sea, the "Old 

' and the " Lark" j 

yet, free of it, except 

just above their confluences. Looking at these facts, I would 
a^k, it it be a native, how is it that it has never exhibited 
its extraordinary powers of increase till now ? For if it be 

not new, we must suppose that a new property has recently 
been imparted to it, which is absurd; and what better proof 
of its newness can be offered than by the facts made patent, 
that it is only now in the act of descending our rivers. To 
my mind, the evidence is conclusive that it is a foreign 
importation, and it is only when we are satisfied on that point 
that we can properly discuss the question of whence came it? 
Now this is a point on which no ex cathedra dictum can at 
present be pronounced. The question can only be settled by 
a careful comparison of our plant with its congeners in other 
countries. It appears, however, that plants of the genus 
"Anacharis" are confined to the American continent, and 
that one plant, called « Anacharis Nuttalli," or « Udora 
Canadensis," very closely resembling, if not identical with 
ours, is found in the American rivers. Dr. Johnston has 
specimens from Dr. Maclagan, gathered in Detroit Biver, 
which exactly resembled his Berwickshire plant, save only 
a slight difference in the outline of the leaves. 

The American plant is frequent in the rivers from Canada 
to Virginia. I think, therefore, we may safely answer the 
question of « whence it came," by saying, << From North 
America." * 

But, then, how did he get here ? Now there are various 
ways in which a plant may be imported. A Botanist, in the 
ardour of that Botanical instinct which prompts him to 
surround himself with as many as possible of the beautiful 
and varied forms of vegetable life, might have introduced it ; 
but we have no evidence that such has been the case, although 
Botanists have been known to do such things. If one might 
hazard a conjecture, I should say that it was most likely 
introduced at or about Rugby, with American timber, durino- 

Northern Europe, I ca: 

of the_ Stamford Mercury, 
i plant 13 an import 

■ ' ..■■;,.■..,.: 

tme of the numerous railways which meet 
at that point. We know that in North America the timber 
is floated in rafts down the rivers, in which case fragments of 
the American weed would cling to it, or seeds might find 
their way into the clefts of the wood, and if but one seed, or 
one fragment retained its vitality, in some moist cranny, till it 
reached its final destination, I verily believe it would be 
sufficient to account for the myriads of individuals that now 
exist in England. Indeed, from the circumstance of all the 
plants hitherto found being of one sex, the hypothesis of its 
propagation from a single seed or fragment is rendered more 
probable than by supposing a number of seeds or fragments 
to have been imported. 

But some one will be asking, as the plant could not have 
found its way by water from Rugby or Watford to Cam- 
bridge, how came it in the Cam ? This question through the 
kindness of Mr. Babington, I am enabled to answer dis- 
tinctly. In 1847, a specimen from the Foxton Locks was 
planted in a tub in the Cambridge Botanical Garden, and in 
1848, the late Mr. Murray, the curator, placed a piece of 
it in the Conduil - by the new garden. In 

the following year, on Mr. Babington asking what had 
become of the stick which marked the site of the plant, he 
was informed that it had spread all over the ditch. From 
this point it doubtless escaped by the waste pipe across the 
TrumpingtoD Koad, into the <•' Vicar's Brook," and from 
thence into the river, above the Mills, where it is now found 
in the greatest profusion. In the case of the Cam, then, we 
see it proved to demonstration that the short space of four 
years has been sufficient for one small piece of the " Anacharis" 
to multiply so as to impede both navigation and drainage. 
When Professor Gray, of Boston, U.S., was at Cam- 
bridge, Mr. Babington mentioned the circumstances to him, 
at which he expressed surprise, as the Anacharis is not found 

to spread in this active manner in America. Perhaps our 
sluggish streams, the decomposing vegetable and animal 
matters in our Cambridge waters, and especially the excess 
of lime present, (15 to 17 grains in the gallon), furnishing 
an inexhaustable supply of inorganic food, may account for 
its more rapid increase here than in America. 

Lastly: with respect to the question,— 7/«w is it to be got 
rid of? I think we may answer it at once by an emphatic 
" not at all." Like the imported European horses and 
oxen in the South American Pampas, or Capt. Cook's pigs 
in New Zealand, or the Norway rat in our own farm yards, 
or the Oriental black beetle in London kitchens, or (more 
remarkable still) like the exotic mollusk (the Dreissena 
Polymorpha), which has now spread itself through the canals 
of this country, we may conclude it has fairly established 
itself amongst us, never to be eradicated. All we shall be 
able to do is to try and keep it down, and in order to effect 
this, it should not be left in the rivers after being cut, in the 
hope of its finding its way to sea; but be raked out at once 
upon the shores ; and Commissioners of Drainage should 
beware of letting fresh tvater into their districts, for the weed 
will inevitably enter with it, and blockade the ditches. 

In conclusion, Mr. Editor, you must allow me to remark 
(while warmly thanking you for your courtesy in affording 
me so much space in your valuable journal), that I should 
never have obtruded myself on the public if I did not re- 
cognize in the introduction of this "New Water Weed" 
beyond the mere scientific question, considerations of much 
local and economical importance to this Fen country. 

Yours obediently, 
Ely, August 30th, 1852. W. MARSHALL.