XU PREFACE. 
the help of figures, he will require either the Historia 
Muscorum of Dillenius, the Hydrophyta Danica of Lyng- 
bye, the System der Pilze und Schwamm of Esenbeck, or 
Sowerby’s English Fungi, according to his peculiar views. 
With the view of assisting those students who have been 
accustomed to use the Linnzean mode of investigating plants, : 
there is prefixed to the second volume, which contains the 
perfect, or phenogamous, plants, an analytical guide to the 
families, according to the number of the sexual organs. 
It remains then only to say a few words respecting the 
index. In general, the Latin generic names only have 
been quoted, but when a genus contains a great number of 
species, as agaricus, lichen, conferva, rosa, juncus, and some 
others, the trivial names are referred to, or the second word 
of the specific difference, if the plant had no name given to 
it by the old botanists. In a few cases, when the second 
word was an adjective, agreeing not with the generic name, 
but with a following substantive, this adjective is omitted, 
and the governing substantive inserted, as bryum perangustis 
crebrioribus foliis, &c. of Dillenius in Raii Synopsis, is 
referred to in the index under Bryum foliis. 
As to English names, a considerable number of new ones 
have, for the sake of system, been given to the genera of 
plants; in forming the majority of which, the form and 
fashion of our ancient names have been as closely adhered 
to as was possible; but, in some instances, Anglicized Latin 
names are used: these, however, ought to be regarded as 
only temporary. In regard to the manner in which com- 
pound English names are inserted in an index, a considerable 
difference is observable in authors. Some few insert them 
as they are spoken, as plough mans’ spike nard under P, 
evening prim rose under E. Other authors seem to consider 
-spike nard and prim rose as generic names, and place them 
under S and P. Some carelessly insert them without any 
regular rule, so that a person is frequently obliged to search 
for all the words of which a name is composed before he 
finds the reference. ‘To avoid this, a general rule has been 
