Equisefum . ] 
FERNS. 
81 
2. — EQUISETUM DRUMMONDIT. 
BLUNT-TOPPED HORSE-TAIL. 
(Plate IX, fig. 2.) 
Cha. — Barren stem blunt, erect, with about twelve branches. 
Fei-tile stems with adpressed sheaths with 1 -ribbed teeth. 
Syn. — Equisetum Dnuumondii, Hook, in E. B. Suppl . ; Mack., FI. Hib . — 
E. umbrosum, Willd., Hook., and Arnott, Bab. 
Fig. — E. B. Suppl., t. 21Ti. 
Des. — Barren stem exceedingly delicate, finely tapering upwards, 
with about 20 grooves, very rough on the angles, with white and 
shining particles of silex, 12 inches high, of a pale, lightish green, 
particularly the sheaths, which widen upwards, six or eight in 
number, rather close together, with long, black, terminal teeth. 
This plant differs from Equisetum arvense in its more glaucous green colour, 
very much more delicate habit both of stem and branches, and blunter outline. 
The fertile frond is much more rigid in texture, with harder, whiter, and more 
numerously-toothed sheaths, and the points of the teeth are more diaphanous 
than in the next species. 
Hab. — First found by Mr. T. Drummond at Wolf Hill, the seat of W. 
Thompson, Esq., near Belfast. 
3.— EQUISETUM ARVENSE. 
CORN HORSE-TAIL. 
(Plate IX, fig. 3.) 
Ciia. — Barren stem taper-pointed, decumbent. Sheaths of the 
fertile stem three or four, distant, loose. 
Syn. — Equisetum arvense, Linn., Willd., Smith, Hook., Bolt., Ehrh., Huds., 
Liffhtf., With., Pursh, Mack., Gray . — Equisetum segetale, Ger. 
Fig. — E.B. 2020. — Bolt. 34. — Flo. Lon. 64. — Ger. Her. 1114. — Park. 1202. 
Des. — Main stem of the barren frond with few grooves, pro- 
cumbent, tapering to the end, sometimes very long, pointed, rough, 
with whorls of branches all the way down, and forked at the base ; 
that is to say, two or more stems springing from the same part of 
the rootstock. Branches simple, varying much in number, fourteen 
or sixteen, if all are present, but generally not more than eight or 
ten, or even six, at the upper part of the stem. They are dark green, 
rough, four channeled, with simple angles. Fertile fronds appearing 
before the others, light brown, with four or five distant, deeply- 
toothed sheaths. The teeth are sharp, ribbed, and rather dark 
coloured, particularly round their edges. As the fertile frond comes 
to maturity, the sheaths decay from the point downwards ; thus 
