440 OBSERVATIONS ON THE GENUS HEMITELIA. 
name will revert to the group of ferns, for which it was 
originally intended, and Cnemidaria must consequently be 
abolished—Hemitelia, thus reduced, forming a very natural 
genus, characterised by its bipinnate fronds, furcate veins, the 
lower branches of the inferior ones anastomosing and form- 
ing an arch between each pinnule, and by the half cup-shaped 
persistent indusium. 
r. Brown is still of opinion that H. Capensis and H. 
multiflora ought to constitute part of his genus, and, as- 
suredly, no botanist has clearer ideas respecting the 
limits of Genera. But as it is now admitted by every one 
that no such thing as a genus exists in nature, and that the 
groups of species which we designate by that name are only 
conventional, more than one character must be taken into 
consideration in constituting them; that is, if we wish them 
to be natural. If the nature and position of the indusium 
alone are to be admitted as therule to form genera, or the 
venation alone, or the position of the sorus, or habit, we de- 
part from that which every one is at present wishing to arrive 
at—a natural classification. Keeping this principle in view, 
I cannot see why H. horrida, for example, and H. Capensis, 
should be considered congeners; nor why H. multiflora 
should be placed in Alsophila, as that genus is now 
defined. 1f, however, more than one circumstance is to 
be regarded in the formation of genera, these two species will 
compose a very l genus, as nearly intermediate as possi- 
ble between Hemitelia and Alsophila. Mr. Smith has not yet 
published his observations on this tribe of ferns, but I learn 
from him that he has considerably modified the character of 
Alsophila, and divided it into four sections, of which Hemitelia 
Capensis and multiflora form one. He has likewise done 
away with Cnemidaria of Presl, and retains Hemitelia for H. 
horrida, and its allies. 
The genus which I now propose to constitute I have named 
from åpðw, and xécpyos, because one of the species is common 
both to the old and the new world. 
