38 
FERNS. 
[. Aspidium . 
Syn. — -Aspidium aculeatum, Swz., Willd., Hook, in B. FI. ed. 4, Hook, and 
Arnott, Smith, Gulp., Mack., Gray. — Aspidium lobatum, Hook, in FI. Scot., 
Schk. — Polypodium aculeatum, Linn., Huds., Light/., Ehrh. — Polystichum 
aculeatum, Roth., Decan. — Polystichum angulare, Bab., 1851, Moore, 1853, 
Neivm., 1854. — P. aculeatum a, Bab., 1851, Moore, 1853. 
Fig. — E. B. 1562.— Pluk. Phyt. 180 /. 1 ( not good). 
Des. — Rootstock tufted. Leaves numerous, perfectly lanceolate, 
evergreen, bipinnate. Pinnae alternate, gradually tapering, close 
together, their midribs covered with hair-like scales. Pinnules ovate, 
distinctly stalked, serrate, spinulose, and with an auricle on the 
upper side at the base of each ; that next the rachis larger than the 
rest, but not so much so as in the last species ; all remaining distinct 
from each other nearly to the point of the pinna, although some- 
times so crowded as to overlap. Leaf-stalk clothed with pinnae to its 
base, and very scaly. Sori distinct, brown, small. Indusium orbi- 
cular, fixed by its centre, soon withering. 
This plant varies much in the sharper or blunter shape of the lobes of the leaves, 
for which reason it is sometimes extremely difficult to decide if a leaf be of this 
species or the former. Luxuriant plants assume much the appearance of lobatum, 
as the large pinnules become slightly decurrent ; but in this state they become 
somewhat deeply cut, or even compound, while in the last species they are truly 
entire, losing their serratures instead of becoming more cleft by culture. 
(3. Pinnules short, blunt, thin, and membranaceous, distinctly auricled. Rachis 
very chaffy. Aspidium angulare, Smith in E. FI., Hook., Mack., Willd. A. 
aculeatum [3, Smith, in FI. Br. Fig. — Plate ii, f. 6 (3. E. B. Sapp. 2776. 
y (linearis), (angustatum, Moore, 1853.) Pinnules linear and very sharp- 
pointed. Fig. — Plate ii, f. 6 y. 
These are well-marked varieties, yet not sufficiently distinct either in habit or 
character to constitute separate species. The var. (3 has, when luxuriant, its lower 
and larger pinnae compound (Polystichum angulare, var. subtripinnatum, Moore, 
1853) ; when it becomes of course subtripinnate, and larger (but not comparatively 
aculeatum and A. angulare as distinct species, it is necessary that I should state the reasons 
why I have blended these two plants together. I have not been guided by any desire of inno- 
vation, believing unsteadiness of nomenclature and of classification to be the bane of science, 
but because after the most careful examination of specimens from all parts of Great Britain 
where they grow, and after consulting all the most celebrated practical botanists that 1 have 
the honour to be acquainted with, I have found it absolutely impossible to draw the line of 
demarcation between the plants. To delineate extreme states of any variable plant is easy 
enough, but where there is so regular a gradation from the robust pointed pinnules to the 
blunt and delicate ones, the difficulties of discrimination are insurmountable. Also, upon 
writing to various gentlemen for specimens and habitats, I have received the same plant 
repeatedly under the two names, and it is very remarkable that the habitats received inva- 
riably refer to both varieties, though they have not always been received from the same 
person. Thus Dr. Johnston says, that both grow at Peasebridge, Berwickshire; Mr. Bowman 
says of Aculeatum, near Richmond, Yorkshire; while Mr. J. Tatham notes the same place 
as a station for the Angulare. Thus doubts arise if the same or different plants are indicated. 
The name Angulare appears, however, by far the more commonly given to it, and 1 should 
for this reason have preferred it to Aculeatum, in deference to the opinion of my countrymen; 
but foreigners give the name Angulare to an Hungarian Fern very different from ours, and 
as Aculeatum is the specific name of all authors who have combined the two Ferns, and is 
besides more expressive, I have adopted it. 
