SCALY SPLEENWORT. 
303 
indications of being a record of real observation, and yet what 
is said of the involucre does not convey an exact idea of its 
appearance. I am not prepared to say that this very accurate 
author is wrong in thus describing a double involucre ; but 
granting that the second is an involucre, its great discrepancy 
in prominence should surely have been noticed. Willdenow, 
Swartz, Sadler and Hooker, deny the existence of an involucre 
in Ceterach^ and thus totally destroy its natural affinity wdth the 
AspleniacecB. For a long time, owing to a too hurried and su- 
perficial examination, I overlooked this important character, and 
I am indebted to Mr. Wilson for first calling my attention to its 
existence. I now fully concur in Mr. Wilson’s views as to its 
presence. Mr. White and Mr. Jenner have also kindly and zea- 
lously assisted in the enquiry with a similar result. 
Mr. Wilson considers that some of the scales which cover the 
back of the frond are ranged in a linear series on the involucre 
itself : this observation I have been unable to verify, probably 
from my want of skill in manipulation. In order to obtain a 
perfectly satisfactory view of these parts, it is not only necessary 
to obtain fronds in a very young state, even before they are 
fully unfolded, and before they have had the least opportunity 
to become dry or withered, but it is also requisite carefully to 
denude the frond of its scales, removing them one by one while 
the object is still under the glass. Whoever may hereafter take 
this trouble, will, I am persuaded, fully concur with me in as- 
signing to Ceterach a true involucre, closely resembling that so 
observable in the genus Asplenium. 
Mr. Smith, of Kew, without whose concurrence I scarcely 
feel confident of even my own observations, has favoured me 
with his views on this interesting subject. It will be seen by 
the following quotation from his letter that he has not yet 
larum copiam et densitatem segre discernendos e duplici capsularum serie con- 
flatas, tectse Involucro duplici, membranaceo, superficiario, in medio demum 
secundum longitudinem dehiscente, bivalvi et tandem effusis capsulis per to- 
tam segmenti paginam, non ultra distinguendo. Capsulae subrotundae, pellu- 
cidaB, annulo articulato, purpureo, minus pellucido cinctae. Semina fusca, 
exigua. — Roth, Flor. Germ. iii. 49. 
