40 ferns. [ Aspidium. 
Suffolk, Mr. Davy. Oxton Bogs Notts, Dr. Howitt and Mr. T. Cooper ; and 
lately discovered on Edgefield Heath, and at Fritton, Norfolk, by Mr. Wigham, 
of Norwich. Even one of these habitats may, perhaps, be now expunged, as 
Mr. Dennes informs me it is thirty years since it was last found at the Lows in 
Holt-heath. It was stated on page 70, of the first edition, that I had reason to 
believe that this plant grew on Wimbledon Common; this was an error of 
judgment or of memory in my informant. It does not grow there, but the A. 
spinulosum does. Mr. Mackay admits it into the Irish Flora, as growing in the 
grounds of Sir H. Gough, at Rathronan, near Clonmel, found there by Mr. 
G. S. Gough, in 1835 ; he says that the Irish plant is acutely serrate. 
Geo. — Oldenburgh, Bremen, Mecklenburgh, Hanover, and other parts of 
Germany. New York to Virginia. 
8.— ASPIDIUM RIGIDUM. 
RIGID SHIELD-FERN. 
(Plate 3, fig. 5.) 
Ciia. — Frond bipinnate. Pinnae alternate. Lobes oblong, de- 
current, tridentate. Rachis scaly. 
Syn. — Aspidium rigidum, Hook, in Bri. Flo., ed. 3 and 4, Swz., Schk . — 
Aspidium spinulosum, Hook, in Bri. Flo., ed. 1. — Polypodium rigidum, 
Hoffm. — Polystichum rigidum, Decan. — Polystichum strigosum, Roth . — 
Lastraea rigida, Presl, Newm. 
Fig. — E. B. supp. 2724. — Schk.fil. t. 38. — Newm. page 50. 
Des. — Root tufted. Rachis thick, rigid, very scaly all the way 
up. Frond lanceolate, not contracted below, erect, from one to two 
feet high. Pinnae tapering, alternate, very close together, from 
thirty to forty pairs, their stipes very much thickened at their 
union with the rachis. Lobes distinct, decurrent, oblong, blunt, 
tridentate, but not spinulose, their midrib waved. Sori large and 
abundant, chiefly on the upper part of the frond. Indusium round 
reniform, persistent, with a glandular margin, white at first, lead- 
colored afterwards, covering the whole mass of thecae, &c. 
Much diversity of opinion has existed respecting the identity of this very distinct 
plant, a small state of the spinulosum being very often sent for it. Its generally 
alternate pinnae would be perhaps sufficient to distinguish the two, but in other 
respects it differs essentially from that more common species. The rachis 
of the rigidum is very scaly and very much thicker than in the spinulosum, 
its pinna; much more numerous and nearer together, the lower pair not broader 
than the rest, the lobes of all quite decurrent, and not by any means spinulose, 
besides which the indusia are very large, and so different, as at once to distinguish 
the two plants ; in addition to which it may be remarked, that Aspidium rigidum 
is much darker in color than the spinulosum, as it is also than the cristatum. It 
is intermediate between the last and next species in the number of its divisions, 
but does not resemble either of them in habit or appearance. Mr. Newman, and 
the late Professor Don, both support me in the identity of this species with the 
Aspidium rigidum of Schkuhr, specimens from whom I have seen. Mr. Newman 
justly remarks that, “ when cultivated, it assumes a more diffuse and lax appear- 
ance, and is not so like Schkuhr’s figure as the plant from Settle.” 
