26 
EQUISETACE^. 
Moist banks near a waterfall, at the upper end of Colin Glen, 
Belfast, where I found it, in company with Mr. F. Whitla, in 
August, 1833.” I gave the substance of this statement in ^The 
Phytologist,’^ and named the plant in honor of Mr. Mackay ; sup- 
posing him the original discoverer of the plant, I thought it a 
compliment justly due to so distinguished a botanist. Since its 
first discovery it has been found by Mr. Moore in many of the 
glens in the North of Ireland, particularly in Ballyharrigan glen 
(Derry), and in the wild deep ravines emphatically called “ The 
Glens ” (Antrim). In Scotland it was first discovered in 1841, 
on the banks and in what is usually the bed of the river ” 
Dee, in Aberdeenshire, by Mr. Brichan ; and I have to acknow- 
ledge the great obligation I am under, both to Mr. Moore and 
Mr. Brichan, for a supply of specimens, recent and dried, so 
that I have had the best possible opportunity for a careful in- 
vestigation and comparison of the plants from the Scotch and 
Irish localities, and have no hesitation in pronouncing them 
identical ; an opinion in which I believe all botanists who have 
compared them fully concur. 
Its discovery caused a multiplicity of correspondence among 
botanists, some maintaining that it was merely an elongate and 
exuberant form of Equisetum variegatum ; others that it was a 
good species, perfectly distinct from any which had been previ- 
ously recorded as British. The matter rested thus until the 
question was referred to Sir W. J. Hooker, and that illustrious 
botanist decided not only in favor of its distinctness as a spe- 
cies, but pronounced it to be the Equisetum elongatum of 
Willdenow, ( see ‘ London Journal of Botany,’ 42, and Phytol. 
174). Feeling as I do the difficulty under which I shall labour 
in venturing to differ from so high an authority as Sir William 
Hooker, I must still record my opinion that the plant before me 
is not identical with the Equis. elongatum of Willdenow't and 
^ Phytologlst, 306. 
f Equisetum elongatum, W. E. caulibus subduplicato-ramosis, ramis sub- 
ternis scabriusculis sexsulcatis, dentibus vaginanim meinbranaceis, W. 
E. {ramosisshnum), caule striato ramosissimo, ramis virgatis striatis ereclis 
verticillatis, apice floriferis. Desf. Atl. ii. p. 398 ? 
Caulis tripedalis et altior quasi scandens, siibduplicato ramosus, profunde 
