514 
him copied by Linnaeus, who never saw the plant, had long ap- 
peared to me to be very doubtful. I had, however, an opportunity, 
some time ago, of satisfying myself on this subject. I happened 
to receive some mosses as package to plants from America ; and, 
upon examining them, found a /umgermannia and a Splachnum in 
fructification. I suspected the /ungermannia to be the same with 
the Porella of Dillenius ; but this could not be ascertained without 
actually comparing the two specimens, which I had an. opportu- 
nity of doing by the indulgence of Dr. Sibthorp, of Oxford, who 
permitted me to compare my mosses with Dillenius’s original col- 
lection; and, upon the most careful examination, I found my 
_Jungermannia to agree exactly with his Pored/a, but could find no 
fructification upon his specimens. 
“ As I have no doubt that my /ungermannia and his Porella are 
one and the same plant, I shall next endeavor to trace how Dille- 
nius has fallen into this error; for the plant has exactly the habit 
of a/ungermannia. This was, probably, by receiving an imper- 
fect specimen ; as the vagina, when damaged either’ by. the weather 
or by insects, after the tender flower had fallen off, would very 
much resemble the capsule which he has figured. 
His figure of the plant is too much crowded with leaves ; but 
in his original drawings, in the possession of Sir Joseph Banks, the 
leaves, so far as they are represented, are placed in the same man- 
ner as in the annexed figure. I shall ‘now subjoin a description 
of it under the name of Jungermannia porella.” 
The subjoined description and “annexed figure,”~ though 
somewhat incomplete according to modern standards, are very 
clearly based upon the plant of the eastern United States known as 
Madotheca Porella Nees, or, more recently, as Porella pinnata L. 
In 1822 Dumortier established the genus Madotheca, based upon 
Jungermannia platyphylla, J. thuja, and J. laevigata. This name 
was taken up by Nees, who included in the genus the Jungermannia 
Porella of Dickson, and Madotheca came into general use as the 
‘ appellation of this very natural generic group. Lindberg, in 
1869, restored the Dillenian and Linnaean Pore//a and has been 
followed in this by Stephani (in some, at least, of his papers), 
_ Spruce, Massalongo, Underwood, Pearson, Evans, and others. — 
