42 
T. G. HALLE, 
(Schwed. Südpolar-Exp. 
discarded altogether. It is clear, however, that such a manner of solving the ques- 
tion is in flagrant opposition to the rules of priority at present accepted. The right 
course would be to keep the name Pachypteris for the species showing the charac- 
ters of Saporta’s Scleropteris in as far as that genus is founded on the type-species 
of Pachypteris Brgn. A number of species of Scleropteris have now been described, 
and the genus evidently fills a place in the artificial system. It seems as if there 
might be a certain, though rather vague, difference between Scleropteris Phillipsii SAP. 
(= Pachypteris lanceolata Brgn.) and similar forms on one side and on the other 
the remaining species described by Saporta, of which S'. Ponielii Sap. may be re- 
garded as the type. The difference is mainty one of size, the Pachypteris-grou-Ç) 
having considerably larger pinnæ and pinnules. There appears to be some slight 
difference in the venation, too. In the species of the S'. Poinelii-iyY)t, the veins in 
each pinnule are fewer, the secondary veins less straight and parallel and the midrib 
very indistinct or wanting. The venation represents on the whole a wider departure 
from the Thiiinfeldia-ty\)Q than in the original species of Pachypteris. These dif- 
ferences certainly do not call for a generic separation of Pachypteris lanceolata and 
the species of the Scleropteris Ponielii-\.y'pç.\ but such a separation appears desirable 
if the relation between Pachypteris Brgn. and Thinnfeldia Ett., as set forth above, 
is kept in mind. 
Closely related to Pachypteris lanceolata Brgn., which, on account of its too 
little characteri.stic venation, is not suitable as the type for a new genus, there are 
thus, on one side the species of Thinnfeldia Ett., on the other those referred to 
Scleropteris Sap. The differences between each of the two last-named genera and 
Pachypteris are hardly sufficient to justify their separation from the latter; and 
Pachypteris, being the older name, should therefore be used for all these forms, 
with both Thinnfeldia Ett. and Scleropteris Sap. as simple synonyms. Even a 
superficial examination of the species which should then be attributed to Pachypteris, 
however, shows that the genus, if so delimited, would be much too large and very 
unnatural. The typical Thinnfeldiæ represent together a rather characteristic and 
natural group, and so do, in a somewhat lesser degree, the Scleropteris-s,yitc{es of 
the type of S'. Ponielii; and each of these groups certainly deserves to be kept 
apart from the other. Between them there is the Pachypteris lanceolata-ly'pQ, which 
shows resemblance to both. Under these circumstances, it seems better to keep the 
genus Pachypteris in a restricted sense, for plants of the P. lanceolata-lyçç., and 
retain, for the present at least, both Thinnfeldia Ett. and Scleropteris Sap., re- 
garding as type for the latter genus S'. Ponielii Sap. The generic differences are, 
it must be admitted, very vague, but the course is determined by the necessity to 
keep Scleropteris and Thinnfeldia separated, in which case Pachypteris must be 
retained too, as a connecting link. This seems to be the most practical way at 
