22 
NATURE NOTES. 
a more recent arrival (having been first noticed less than half a 
century ago) — is spreading rapidly along the banks of many of 
our rivers. This is one of the Balsams, the Spotted Touch-me- 
not (Impatiens fulva). 
Probably the most familiar of all the strangers which, in our 
own portion of the Eastern Hemisphere, have made themselves so 
thoroughly at home, is the “ American Water-weed,” Anacharis 
canadensis. Introduced into Ireland about 1836, and first noticed 
in this country in 1841, this plant rapidly took almost entire pos- 
session of thousands of acres of water, choking up slow streams 
and ponds, and increasing to such an extent in canals as to render 
necessary the outlay of considerable sums for labour in cutting 
and removing the dense massy growths. In the neighbour- 
hood of Kew this plant is not nearly so abundant as it was some 
years ago ; and in some places it has — after holding undisputed 
sway for a long time— almost disappeared. Whether this is due 
to the exhaustion in the soil of the specific nutriment required 
b} r the plant, or to the purely vegetative reproduction which has 
taken place — the male plant never having been discovered in 
this country until within the last few years in Edinburgh — it is 
impossible to say. The piece of ornamental water between the 
Palm House and the Museum No. 1, at Kew, was, less than 
twenty years ago, one mass of this weed, and much expense was 
incurred in the attempt to keep it under. Water fowl were kept 
there then as they are now, and the late curator, Mr. Smith, did 
not attribute the total disappearance of the Anacharis to the 
agency of the birds. 
If, however, we can charge America with having sent us 
several unwelcome visitors, that continent, as well as most other 
temperate parts of the world, can turn the tables on us very suc- 
cessfully. A goodly number of British plants have made them- 
selves thoroughly at home in far distant lands. Some of our 
thistles have taken possession of immense tracts of land in South 
America, where they assume proportions unknown in our island 
home. I quote the following remarks from a lecture on “ The 
Distribution of the North American Flora,” delivered at the 
Royal Institution of Great Britain by Sir Joseph Hooker some 
years ago. 
“ Whatever countries beyond the seas we may visit, in the 
temperate regions of the globe, we find that their vegetation has 
been invaded, and in many places profoundly modified, by insig- 
nificant plants from other countries; and these are, in almost all 
cases, natives of North-Western Europe. Nearly forty years 
ago I arrived at night at the Falkland Islands, when a boat was 
sent ashore to communicate the ship’s arrival to the Governor. 
Being eager to know something of the vegetation of the Islands, 
I asked the officer in charge of the boat to pluck me any plants 
he could feel for, as it was too dark to see anything ; and the 
armful he brought to me consisted of nothing but the English 
Shepherd’s Purse. On another occasion, landing on a small un- 
