INTRODUCTION. 25 
: as Aspidium, Nephrodium, &c., it will soon be seen 
by any one who studies botanical works, that these 
_ names have no definite signification; thus the same 
group of species is called Dryopteris by Asa Gray 
in America, Polystichum by Roth in Germany, 
Lastrea by Babington in England, and Aspidium 
by Hooker in England. I have never met with a 
botanist really conversant with ferns who in con- 
yersation used either of these terms: it is the in- 
variable plan to use the specific name by itself, as 
Recurvum, Scolopendrium, Ceterach, Trichomanes, 
Viride, &c., and no amount of « generic descriptions,” 
as they are termed, is at all likely to interfere with 
this praiseworthy custom: the object of conversing 
on such subjects is to make ourselves understood, 
not to display the amount of our erudition; and the 
less of Latin or any other unfamiliar language we 
import into our conversation, the better will it 
be relished by all who truly and earnestly desire 
either to learn or to teach. Moreover, these so-called 
“genera” are purely and confessedly artificial; for 
instance, the genus Polypodium was first characterized 
_ by the seeds being arranged in circular masses on 
