UNDERWOOD: REVIEW OF THE GENERA OF FERNS 249 
his own herbarium collection (since his day greatly augmented by 
the vast accumulation of recent and much more perfect examples 
from all parts of the world) is the richest in existence,* and that the 
collection of growing ferns at Kew Gardens is one of the largest 
collections in the world, but with the last circumstance in mind, it 
seems incredible that this collection of living plants has played so 
insignificant a part in the system of generic classification of any ofthe 
Kew workers, with the single exception of John Smith, so long head 
gardener at Kew, whose review of fern generat presents a system 
infinitely more natural, logical, and scientific than that of the 
system under discussion. The merits of Smith's system were in- 
deed recognized by Hooker, but unfortunately not followed in the 
slightest particular in Hooker's later publications nor in those 
which have followed him, as these have faithfully carried out the 
plans which Hooker so clearly laid down. And thus it is that we 
in America have too long continued to speak of the delicate Vephro- 
dium punctilobulum of Michaux as a Dicksonta—a genus based on 
tree ferns of the Southern Hemisphere and belonging to an entirely 
different family from our own species, because, forsooth, all the 
plants of these genera agree in having “inferior cup-shaped or 
bivalved indusia," and in our newly acquired Sandwich Island ter- 
ritory we are asked to regard the noble species of Czdotium in the 
same category! In short the Synopsis Filicum of 1874 with its 
supplements extending to the present time, while describing often 
in too comprehensive a manner (and with little regard for geo- 
graphic distribution as a factor in specific distinctions) five times 
the number of species of ferns of the first Synopsis Filicum of 
1806,t in its representation of genera is little in advance of its 
original namesake. And while Hooker's Species Filicum will 
always stand as a classic in the characterization of species, in its 
* The fern collection at Kew is contained in thirty-six cases, each with sixteen 
compartments 13.5 cm. deep.  Z/eris fills nearly two cases, Asp/enium four cases, 
dum and JVephrodium together six cases, Phegopteris and Polypodium together five 
cases, and Acrostichum ponas two cases. These data will enable those who have never 
visited Kew to form some idea of the vastness of the collection. 
+ Historia Filicum, 1875; and earlier papers commencing with his first discussion 
of Fern genera, Hooker's Journ. Bot. 4: 38-70; 147-198. 1841; London Journ. 
Bot. 1: 419-438; 659-668. 1842. 
tSwartz, Synopsis Filicum, 1806, 
