CRYPTOGAM lA. 3^9 



rence in the accessory, as veil as the essential, 

 parts of their flowers, their bulk being by such a 

 reformation much diminished, it might be advisable 

 to reduce them to one Class, in which tlie slender 

 remains of Polijgamia might commodiously be in- 

 cluded, and the title of such a Class should be 

 Didhila, expi'essing the two distinct scats, or sta- 

 tions, of the organs of fructification. 



Class 24. Cnjptogamla. Stamens and Pistils either 

 not well ascertained, or not to be numbered with 

 any certainty. Orders 5. 



1. Filices. Ferns. The parts of their flowers are 

 almost entirely unknown. The fructification, taken 

 collectively, and proved to be such by the produc- 

 tion of prolific seeds, grows either on the back, 

 summit, or near the base of the frond. Some are 

 called anmilatcc, annulated, their capsules being 

 bound with an elastic transverse ring; others thecatce, 

 or more properly e.vanmdatce, from the want of 

 such an appendage, of which some of the latter 

 have, nevertheless, a spurious vestige. All the 

 former, and some of the latter, are dorsiferous, 

 bearing fruit on the back of the frond, and of these 

 the fructification is either naked, or else covered 

 with a membranous involucrum. The genera are 

 distinguished by Linnagus according to the shape 

 and situation of the spots, or assemblages of cap- 

 sules, besides which I have first found it necessary 

 2 B 



