092 



brown-tipped teetli : 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 ; exteriorly they are quite black, but as they 

 separate about Midsummer, by the ripening of the catkin, a common 

 recej)tacle of ivory whiteness 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 fer- 

 tile 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 unbranched, whether fertile or barren, 

 I have no doubt that it is the 'Equisetum nudum laevius nostras' of 

 E,ay,* the habitat, figm-e, &c., closely corresponding ; this form is also 

 the E. limosum of Linneus, who, in his 'Systema Vegetabilium,' 

 quotes E-ay's description and figure ; but it should also be observed 

 that subsequently, in his ' Flora Lapponica,' he omits all notice what- 

 ever of this unbranched form, evidently not considering it worthy of 

 a place even as a variety. The fertile stem occasionally becomes pro- 

 liferous, 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 recorded in the ' English 

 nora,'t where the author remarks that he has seen no such variety in 

 England. 



The baiTen stem is much longer than the fertile, and varies in an 

 infinity of ways : among a few which I have lately gathered in the 

 ditches of the Isle of Dogs, where this plant abounds, but can scarcely 

 be said to flourish, 1 select the following as instances of variation. 



A — is forty-three inches in length, and has thirty-seven joints, with- 

 out a single branch. 



B — is forty-five inches in length, and has forty joints: from the 

 first to the nineteenth inclusive these are branchless, the twentieth has 

 one branch, the twenty-first two branches, the twenty-second two, and 

 the twenty-third to the fortieth inclusive one branch each. 



* Synopsis, 131, tab. 5, fig. 2, a, b. f English Flora, iv. 326. 



