VARIEGATED EQUISETUM. 
35 
the river E. variegatum of Weber, &c. are certainly indigenous to 
Great Britain, the former being the plant from the sands of 
Barry, New Brighton, &c., and the latter having been found 
by Mr. Johnson, growing on the banks of the canal near Dublin ; 
in several other similar situations, in the same neighbourhood, 
by Mr. Moore ; and in the bed and on the banks of the Dee, in 
Kincardineshire, by Mr, Brichan. The Dublin plant was the 
first of these to claim the attention of botanists, and Mr. Moore, 
after giving the subject every possible attention, gives me his 
views in the following words I have entered into correspon- 
dence with Mr. Wilson respecting the aquatic Equisetum, which 
you take to be a form of E. variegatum^ and wdiich I am con- 
vinced is a perfectly distinct species. Still I admit it is difficult 
to fix on characters to distinguish our aquatic plant from E. va~ 
riegalwn, and I should say the only permanent distinguishing 
marks are the greater size of the former, its different appearance, 
and its habit of growing,but these marks are so constant both in 
a natural and cultivated state that they are worthy of grave con- 
sideration. E. variegatum is a slender creeping plant, its stems 
very decumbent, only rising from the ground near the apex ; 
they never have more than six striae. The aquatic plant is an 
elegant, bold, upright growing species, with the fronds remarka- 
bly straight and stout, and constantly marked with nine or ten 
striae, and although not nearly so much inclined to branch at 
the base, it grows in closer caespitose tufts. Both species retain 
their characters in cultivation, under which I have had them 
growing side by side in peat earth for two years : both are 
thriving remarkably well, and no two species of a genus can 
appear more distinct.” These observations refer to the aquatic 
and sea-shore plants, as growing near Dublin. Mr. Brichan, to 
whom I sent the Dublin canal plant, and to whom we are in- 
debted for such admirable observations on these species, writes 
me as follows : — The Dublin plant, of which you sent me spe- 
cimens, appears to me not only to resemble but to be identical 
with that which grows in the Dee.” I have next to quote a 
comparison, also from the pen of Mr. Brichan, between the semi- 
aquatic and sea-shore plants as growing in Scotland. The sands 
of Barry, Mr, Don’s original locality, and the spot whence we 
D 2 
