20 . LICHENOGRAPHICAL NOTES. 
in the characters which can be relied on for specific distinction 
nd, as for chemical criteria, it is precisely in the tribes in which the 
least increase has taken place that chemical tests have been most freely 
used, and are supposed to be of the greatest service. In the genera 
Cladonia, Parmelia, Lecanora, and Pertusaria, these tests have been most 
largely employed, and the result in no way tends to bear out Dr. Lindsay’s 
statement. 
that there is an essential difference between the higher and lower Lichens 
In Parmelia, out of 44 forms, 37 were named by the older writers ; while 
6 of the 7 additions are varieties distinguished not by chemical or micro- 
scopie, but by external naked-eye characters. 
d 
reducing as the new of Nylander and Leighton ; but it is eminently unfair 
to charge the microscope and chemical tests with making new distinctions, 
of botanists. Of them in particular, the remark of Nylander is true :— 
Facile enim jam diu patuit determinationes anteriores, szepe nec species 
veras nec formas rite definitas respicere, sed notiones solum vagas indicare 
_ found in Nylander's account of Lecidea parasema (Lich. Seand. 217, 218), 
where we see that he confounded it and its varieties, more or less, with 
ete., while the nai sa, lignaria, stigmatea, rospis, and synothea 
to ere synonyms for forms he had already distinguished. 
en, too, there are a great number of plants which the earlier licheno- 
tisi Sa congr. overlooked or regarded as Fungi. indsay 
1mse'1 describes as “ an increasingly large and important oro —for the 
most part of athalline forms se airs, cien em d 
gonia or pycnidia) alone represent the plant; minute in size, frequently 
obscure and difficult of observation, requiring, for the determination of 
