43 
Fourthly.— Although Dr. Allmann speaks of intermediate forms, 
and seems to regard the two species as passing into each other, by 
means of these; I may state that I have carefully searched herbaria 
for such intermediate specimens, but have never found them. 
Fifthly.—If we take a series of acutum, arranged according to size, 
we shall find that certain of them are of the same magnitude as Adi- 
antum-nigrum, while others are abundantly larger, and some are also 
smaller: but all equally differ from Adiantum-nigrum in the multi- 
plicity and acuteness of their divisions ; the smaller specimens being 
equally attenuate, divided, and acute with the larger. In Adiantum- 
nigrum, on the contrary, the smaller fronds are blunted, and less 
divided than the larger ones. 
Culiural. 
Dr. Mackay dissuaded me from giving Asplenium acutum as a spe- 
cies in the second edition of my ‘ British Ferns,’ by stating that it was 
nothing more than a remarkably attenuated, divided, and elegant form 
of Adiantum-nigrum, and returned to the ordinary state under culti- 
vation. I am far from convinced that the facts of the case were 
noticed with sufficient care. J rather incline to regard that eminent 
botanist as having been misled by the unintentional transposition of 
pots or labels. Certain it is that such a disposition to assume a new 
form, or, as it might be termed, to revert to anormal form, has not been 
observed by other cultivators ; the tendency of cultivation being to 
develope and perfect those very characters of greater size, greater 
amount of subdivision, greater attenuation of parts, &c., which origi- 
nally served to distinguish it from its congeners. 
Since I undertook the investigation of this subject, I have obtained 
the valuable assistance of Mr. Watson and Mr. Babington ; and this 
will probably lead to a second paper, in the March number of the 
* Phytologist.’ : 
EpwaRD NEWMAN. 
9, Devonshire St., Bishopsgate, 
January, 1854. 
