494 DR. LINDSAY ON NEW-ZEALAND LICHENS. 
and in this country by Mudd and Leighton, it appears to me greatly more natural 
and simple. With all diffidence, however, I cannot profess to concur in all Nylander’s 
tribal, generic, or specific divisions, or in his grounds therefor; while I feel myself 
compelled, after a careful study of the subject for twelve or fifteen years, to go further 
than he does in the direction of simplicity and naturalness—in the reduction of the pre- 
sent number of book species and varieties, and in the consequent diminution of names, 
giving attention less to minute, trivial, or inconstant anatomical differences than to general 
external resemblances. The principles and practice of the classification of Lichens is, 
however, a subject, as it appears to me, of such interest and importance to the Cryp- 
togamie botanist, that I propose, at some future time, devoting a special essay thereto. 
I. The New-Zealand Sricræ. (Plate LX.) 
New Zealand is, par excellence, the country of the Sticte. Not only do they there 
occur in the greatest absolute as well as relative numbers, but there they attain their 
maximum development, size, and beauty. In Britain, according to the latest authority, 
Mudd, there are thirteen species of the genera Sticta, Stictina, and Ricasolia (into which 
the old genus Sticta has of late years been subdivided by continental lichenologists). 
In New Zealand, on the other hand, aecording to Babington, there are twenty-seven, or 
more than twice as many. They are also numerous in relation to the Parmeliæ, whose 
place they to a great extent occupy in New Zealand, especially in the forests. While in 
Britain the proportion of the Sticte to the Parmeliæ is as 100 to 366, and throughout 
the world generally as 100 to 154, in New Zealand it is as 100 to 84. This prepon- 
derance of the Sticte, their frequently great size and beauty of colouring, and the pro- 
fusion of individuals give a sometimes peculiar character to the foliaceous Lichen-flora 
of New Zealand. 
The S/ict are one of the most variable and puzzling groups of the higher or foliaceous 
Liehens. Asin many other families and genera, extreme forms are sufficiently distinct; 
but if the collector assiduously devotes himself to the study of the same species under 
different conditions of growth in different countries, or even in different parts of the same 
country, his patience and perseverance will be rewarded by the discovery of every inter- 
mediate gradation between forms apparently otherwise the most divergent. The discovery 
of such gradation-forms will, on the one hand, occasionally set at defiance all his endea- 
vours to define or limit species, and, on the other, in certain cases will enable him to 
group two or more supposed autonomous species in one. | 
There are, on the one hand, certain striking uniformities of character throughout the 
genera Sticta, Stictina, and Ricasolia, and, on the other, certain general directions or 
forms of variation which it is convenient to consider in a group in reference especially 
to definition or limitation of species and genera. ; 
1. Spermovones.—The uniformity throughout the three genera just mentioned (which 
I regard, however, as mere subdivisions or groups of the genus Sticta) is, perhaps, most 
striking in regard to the contents or constituents of the spermogones—the spermatia an 
Sterigmata. The former are rod-shaped, and the latter articulated, irregular, and ramos® 
composed of short thick-walled subcubical cellules (figs. 4, 8, 13, 18). Those of S. pul 
