be satisfactorily accounted for by the more advanced state of the 
fructification in the specimen now before us ; for, as I have ob- 
served under Pleopeltis ensifolia, there is not a vestige of the 
involucres to be found upon the old sori or spots of fructification 
in that species. 
My specimens were gathered upon old walls, in the neigh- 
bourhood of Rio de Janeiro, by Professor Raddi of Florence, 
who sent them to me under the name of Pleopeltis angusta 
of Humboldt, but who was afterwards induced, from not find- 
ing the involucres, to refer the plant to Polypodium, with the 
appellation given in the above synonym ; an alteration which, 
in my opinion, would not have taken place, had Professor 
Raddi been aware of the fiigaceous nature of the involucres in 
other species of this genus. 
This is the individual which gave rise to the generic cha- 
racter of Pleopeltis ; and it was first discovered by MM. Hum- 
boldt and BoNPLAND, near Ario, in the Kingdom of Mexico, 
growing in shady places, at a height of 994 toises (about 6000 
feet) above the level of the sea. Those authors observe, that 
its habit much resembles that of Polypodium phymatodes. 
Fig. 1. Portion of the frond, with an old! cluster of capsules, from which 
the involucres have disappeared, as well as many of the capsules them- 
selves, the old stalks of which only remain. Fig. 2, 3. Scales of the 
frond. Fig. 4. Capsule. Fig. 5. Seeds.— -4// more or less magnified. 
