174 DR LAUDER LINDSAY ON THE SPERMOGONES AND PYCNIDES 
terior,—a phenomena unknown in ordinary or true spermatia. The sterigmata, 
each of which bears at its apex a stylospore, are simple, linear, ramose at the 
base, resembling those of Lichina; their length being sometimes so great as 
sth to goth, their breadth x;th. 
Species 1. P. canina, Hoffm. 
The tubercles which constitute the pycnides are generally very obtuse, and 
so closely resemble young apothecia as to be readily mistaken therefor. They 
are usually, however, of a deeper brown colour. The cavity is simple and very 
narrow. The sterigmata are somewhat irregular in outline, and ramose at the 
base; they are almost solid, from thickening deposit in the interior of the cells 
which constitute them. Each sterigma gives off in succession a series of 
stylospores. The contents of these stylospores are semifluid, and almost homo- 
geneous; they become dark brown in iodine water, while the cell-wall, which 
appears thick, is only coloured yellow. The greatest dimension of the stylospores 
is from xath to jaoth; the least from 3th to guth. The length of the sterigmata 
is about ;4th to sth, with a diameter of s,th. Berkey takes the same 
view, apparently, as NyLANDER and myself in regard to the character of the 
corpuscles, which we all agree in calling stylospores,—at least equally with similar 
corpuscles which occur in Lecidea Smithii and other lichens. 
Species 2. P. polydactyla, Hoffm. 
The diameter of the pycnides is from jth to y:th. The stylospores are 
smaller than those of the preceding species, but otherwise the same; their length 
is about guth; their breadth about half as much; they are oval, slightly curved, 
with very obtuse ends. From the characters of the thallus, apothecia, and spores, 
I am led to refer this species to canina, and the character of the pycnides confirms 
me in this opinion. 
SPECIES 3. P. rufescens, Hoffm. 
This and the two preceding species are all cosmopolites. The pycnides are 
as described in P. canina and P. polydactyla. The stylospores are oval, about 
sooth to sth long, and guth to smth broad. This species I refer partly to P. 
canina and partly to P. horizontalis, unless we look upon all the British Peltigeras 
as mere varieties of one species, which I am greatly inclined to do. This genus 
wants simplification in regard to its species, which certainly pass into each other, 
and in this respect it is in the same category with Umbilicaria (Gyrophora), 
Ramalina, and Usnea. 
GENUS IV. Sonorina, Ach. 
In this genus I have not yet succeeded in finding spermogones or pycnides 

