104 PITTONIA. 
besina a genus Abesina ; out of Lycopodium an Acopodium, 
and many more such. But, as I have intimated, we are not 
left to merely infer that the type of Achomanes lies some- 
where in the Trichomanes of Linnzeus; for, having so well 
described the genus that a good pteridologist might, | 
believe, make out the type species withouta word of biblio- 
graphic reference, he yet proceeds to say that the type is a 
certain species of Trichomanes according to Linnseus ; and, 
when he adds to this the further hint that it is among the 
simple-fronded species, it is told us as plainly as need be 
that the type of Achomanes is Trichomanes membranaceum, 
Linn. 
I grant that quedam isa more or less unhappy type-in- 
dication, in that it may be singular, indicating a monotype, 
or it may be plural, indicating a genus of several species ; but 
that is here of no importance. According to Professor 
Underwood’s understanding, as well as my own, about 
generic types, the type-species is the first species enumerated 
in the group. Linneus has a group of simple-fronded 
Trichomanes made up of three species ; but T. membranaceum 
heads the list, and so, even if Necker's quaedam be given the 
plural rendering, that species is still the one type-species of 
Achomanes. Moreover, as compared with the other two 
species of Linneus’ group with simple fronds, this one is 
preéminently simple, for the fronds of the other two are 
pinnatifid; they are only technically simple. The only 
Linnean Trichomanes which is obviously simple-fronded, 
and which no one could at first aem mistake for a fern with 
pinnate frond is this one. 
It will be discovered by any one who will make the 
investigation herein outlined, that this ACHOMANES MEM- 
BRANACEUM (Trichomanes membranaceum, Linn.; Lecanium 
membranaceum, Presl.) is with Linneus, at least in the Species 
Plantarum, the type-species of Trichomanes. But this fact is 
of no importance here. What I am controverting is only 
the statement—a most unfortunate one, surely—that all 
