ON GENERA AND SPECIES. 45 
` Ihave now to notice an important but yet incomplete 
work, the “ Index Filicum,” a synopsis with characters of 
the genera, and an enumeration of the species of Ferns 
with synonyms, and references, &c., &c., by Mr. Thomas 
Moore, Curator of the Garden of Apothecaries, Chelsea ; 
the first part of this work appeared in 1857. The author 
first gives a synopsis of the orders and tribes, followed by 
2 systematic arrangement and characters of the genera, 
each genus illustrated by a woodcut showing the character 
of the venation and position of the sori, also an analytical 
table of the genera and their synonyms. 
With regard to the number of genera the author tells us 
that he has endeavoured “ to hold a middle course between 
the excessive sub-division and the equally inconvenient 
non-division of older genera,” and that the classification 
adopted is based on the plan on which the vascular struc- 
ture is developed, in conjunction with the nature of the 
fructification. He enumerates 186 genera*, which he 
Iclassifies under five orders, namely, Polypodiacee, Maratti- 
| | acece, Ophioglossacec,| Lycopodiacec, and Marsileacee. 
The following abstract will be sufficient to convey an 
idea of Mr. Moore’s method of classification. 
FILICALES, SPORE-CASES. 
ONE-CELLED. 
* Spore-cases furnished with a jointed ring, which is 
usually nearly complete, sometimes rudimentary. 
Order I.—POLYPODIACEJE, 
|| Ring vertical, nearly complete. 
Tribe I.—POoLYPODINEE. 
Linn.) 
cem, which are not taken up in the present work. 
hi 
eh A. Aetoetichee (Ex. Elaphoglossum, Schott. Acrostichum, — 
.* This includes ten genera of the orders Lycopodiacee and Marsilia- . 
