A a ES: —-— 
FILICES. 331 
_. GENERAL ARRANGEMENT OF FERNS. 
from a state of coniparative confusion, nearly to their pre= , Filices. 
sent form. Since the work of Smith, others have follow 
ed on the same principle ; and Bernhardi, Swartz, and 
Sprengel, have respectively contributed to our stock of 
knowledge of these plants. 
The general principles on which the genera are at 
present distinguished, consist in the form, attachment, 
and manner of opening of the involucrum ; and when 
this envelope is wanting, in the manner in which the 
sori (groups) are ' on the receptacle of the 
frond. To receptacle, the capsules are generally 
. ‘attached by a fruit-stalk, in some so short, as to cause 
them appear sessile ; in others of a considerable! a 
and sometimes branched with a capsule on each divi= 
sion. The whether situated on the plane of 
of al , as will soon appear, there are in- 
stances of le multilocular poe aa apparently 
sessile in the frond itself. The capsules in most of the 
tribes are girt with a ring, which, on the maturity of 
the seeds, ee eae ee 
with considerable force to some distance from the plant. 
This ceperenanee may be oherer ss occasionally, b 
placing the ripened under the microscope, wi 
a sheet of writi sper under them to receive the ex 
ploded seeds. a great part e series, many 0 
genera want the rings ; but, instead of them, their cap- 
sules are more or less marked with striz, in the direction 
of which they burst. : 
An attempt is hens, mnade.to..arnenge ‘he, genera, of 
the principle of the natural method, as far as our limited 
knowledge of the structure of their most essential or- 
gans would admit. It is no doubt very likely, that se- 
veral of those we have ventured to i , will 
be found deficient in affinity by uent observers ; 
but as an adherence to truth and nature is the great ob- 
ject, this will only add to our satisfaction ; conscious, 
as the illustrious Jussieu observes, that such errors ori- 
* Non legum naturalium, sed prave eorum in< 
terpretationis, vitio.” 
I. DANEHACEX, (Ptare CCLIV. Fig. 12.4.) - 
(Poropterides, Willd. Sp. Plant.) 
We have commenced with this singular tribe, because 
it differs most the rest of the 
E 
series, it is still more nearly related to them than the 
a aR = a A and Gonoph cee, of which 
The single multilocular seed-vessels, in this tri 
sessile in the substance of the frond, and which, in the 
genus Maratiia, are endowed with a divisible septum, 
renders it necessary to them in a natural method, 
their -vessels possess neither an involucrum 
nor ring, yet their fronds are entirely those of ferns. 
They possess a similar structure. They are inyolute, or 
circinate as it is termed, in their vernation, and affect a 
imi in their fruit they are singu- 
larly distinct ; for instead of the groups of minute cap- 
sules, as in the greater part of the series, this tribe is 
GENERA, 
( 1) Marattia. (Sm. Act. Taur. 5. p.419. Myriotheca, 
uss. Gen. Pl. p..15. Willden. Sp. Pi. 5. 1942.) 
Seed-vessels oval, distant, with a divisible or double 
