ON GENERA AND SPECIES. 55 
Presl by placing Matonia in alliance with Cyathea, with 
which in habit and even in. technical character no generic 
affinity is traceable. 
In his general arrangement he follows, with a partial 
exception, the sequence of Presl, arranging the whole 
under two sub-orders, Gleicheniacee and Polypodiacece, the 
latter consisting of twelve tribes, beginning with Cyathea, 
including Hymenophyllum, and ending with Acrostichum. 
With regard to Asplenium, Polypodium, and Aspidium, he, 
in a great degree, follows Mettenius and Fée's arrange- 
ment and descriptions of Acrostichum. 
From what has now been stated it will be seen tbat, 
although Sir W. Hooker bestows great praise on his con- 
temporaries, he nevertheless adopts but few of their genera, 
thus making it appear that but little advance has been 
cum in our knowledge of the natural habit and anato- 
mical structure of Ferns since the time of Sprengel (1827). 
He, however, finds himself compelled to divide his large 
genera into sections, which are equivalent to the genera of 
authors ; indeed, it is only by the sections that we are 
saved the labour of wading through 200 or 300 species in 
order to find out a single individual. 
. The following is a tabular view of the sequence of 
the tribes and genera as arranged in the “ Species 
Filicum " :— 
OnpEz I.—FILICES. 
Sub-Order 1.—GULEICHENIACE£. 
. Gen. 2. Platyzoma, Gleichenia. 
Sub-Order 1I. —PorYvPODIACE&. 
Tribe L--Cramuz. 
Gen. 3. Cyathea, Hemitelia, Alsophila. 
