56 
EQUISETACE.E. 
the second to the seventh internode inclusive. The branches in 
each whorl vary from five to seventeen in number : they are di- 
vided into joints, varying from five to ten in number, and have 
from five to eight striae, with corresponding ridges. Each of 
these ridges becomes double or divided on entering the sheath, 
but the two portions are again united before terminating in the 
extreme points of the brown-tipped teeth : the internodes of 
these branches are extremely variable in length, the first and 
last being the shortest : the branches also vary greatly in length. 
The catkin is short, ovate, gibbous and terminal ; and the 
stalk on which it stands is short, scarcely exceeding in length 
the sheath which encloses it. I can discover no apiculus, the 
extreme summit being composed of scales similar to the rest : 
these are generally more than a hundred in number ; externally 
they are quite black, but as they separate about Midsummer, by 
the ripening of the catkin, a common receptacle of ivory white- 
ness is disclosed. 
This species is extremely subject to variation, so much so 
that the preceding description will only suffice to give a general 
idea of a fertile stem. Some are entirely unbranched, others 
sparingly branched, and others again more numerously branched : 
the site of the branches also varies, commencing variously at the 
second, third, fourth, fifth, sixth or seventh sheath, and forming 
two, three, four, five, six, seven or eight whorls. When quite 
imbranched, whether fertile or barren, I have no doubt that it is 
the ^Equisetum nudum Icevius nostras'' of Ray,^' the habitat, fi- 
gure, &c., closely corresponding; this form is also the E. limosum 
of Linneus, who, in his ‘ Sy sterna Vegetabilium,’ quotes Ray’s 
description and figure ; but it should also be observed that sub- 
sequently, in his ‘ Flora Lapponica,’ he omits all notice what- 
ever of this unbranched form, apparently not considering it 
worthy of a place even as a variety. The fertile stem occasionally 
becomes proliferous, as in the preceding species, but much more 
rarely. Mr. Luxford possesses a specimen of this kind, found 
in a mill-pool, by the Bristol-road, Birmingham ; and in Sir J. 
E. Smith’s herbarium is a Swiss specimen from Mr. Davall, as 
8_yiiO])sis, 131, tab. 5, 2, a, b. 
