00 
EQUISETACE^. 
The barren differs from the exclusively fertile stem in having 
the sheaths much smaller and more distant ; the teeth also are 
shorter, fewer in number, and less pointed. The barren stem 
is generally about eighteen inches in length, and is usually divided 
into about twenty joints, of which the four or five lower ones are 
branchless, but each of the others is furnished with a whorl of 
branches varying in number from ten to sixteen in each whorl. 
These branches at first are somewhat recurved and drooping, as 
in E. sylvaticmn, but they afterwards become spreading and 
slightly ascending ; they are simple, and composed of eight or 
ten joints, of which the basal one is the shortest, being a mere 
sheath ; the second is sinuous : they are usually three-ribbed, 
and the loose sheath which accompanies each joint terminates 
in three obtuse teeth, which have the extreme tips brownish ; 
the ribs become diffused, and their integrity lost, before reaching 
the extremities of the teeth. The ridges of the stem and 
branches are beset with siliceous points, which give the plant a 
rougher feel than the preceding. 
Sir W. J. Hooker observes — Its nearest affinity is doubtless 
with E. arvense, but it is abundantly distinct. Its colour is 
greener and less glaucous ; its stem rougher, with closely-set 
raised points ; its angles and branches much more numerous ; 
and the whole barren frond is singularly blunt in its outline or 
circumscription at the extremity, by which it may be at once 
known from E. arvense. The sheaths, though paler at the base, 
have blacker and more prominent ribs upwards, and they are 
so close as almost to imbricate each other. The teeth are also 
more numerous, when they separate into their proper number.”^ 
I quite agree with this profound botanist in considering the 
present species abundantly distinct from E. arvense; indeed the 
similarity to that plant does not appear to me particularly ob- 
vious : my idea of what would be termed “its affinities” will 
perhaps be sufficiently expressed by my placing it between E. 
si/lvaticum and E. Telmateia. 
* Eng. Bot. Suppl. 2777. 
