24 
NEW BRITISH LICHENS. 
spores brown, 5-7 septate, 0*018-23 mm. long, 0*006-7 mm. thick ; 
hymenial gelatine tawny wine-coloured with iodine. 
On quartzose rocks in Jersey ( Larbalestier). 
2. Endococcus erraticus* microphorus. Nyl . — 
This differs from the type in the smaller spores (0*004-7 mm. long, 
0*002-3 mm. thick). 
On various crustaceous Lichens in nearly the whole of Europe — 
(sometimes also parasitic on their apothecia !). N. Wales, Car- 
diganshire (W. Joshua). 
OBSERVATIONS ON FARM ELIA OLIVACEA AND ITS 
BRITISH ALLIES. 
By the Rev. J. M. Crombie, F.L.S. 
There had been considerable confusion amongst lichenists as 
to the species belonging to the interesting subsection of Parnielia 
olivacea . Hence various plants totally distinct, both in external 
and internal characters have either not been distinguished at all or 
have been regarded as mere varieties of one or two accepted 
types. We owe it to the critical skill and accurate observations 
of Nyl and er that such clear light has now been thrown upon all 
the known plants of this subsection, that we can now with 
facility assign to them their proper position, whether as species 
or as varieties. It will therefore be of service to British lichenists 
that I should here indicate generally the leading characteristics 
and the general distinction of the different species and varieties, 
according to their Nylanderian conception, which are known to 
occur in this country. 
1. Parnielia olivacea, Ach. 
This species has very seldom been rightly understood by 
lichenists, and though they have given the description of Acharius 
quite accurately, yet in published Exsciccati, they have usually 
issued specimens which do not at all agree with that description. 
It may, however, be easily distinguished by the rugose thallus and 
the entire or nearly entire margin of the apothecia. It is essen- 
tially a boreal species, which is met with only very rarely in the 
Scottish Highlands, although like several other subarctic or 
alt-alpine lichens, e.g ., Stereocanlon paschale , Usne aplicata , 
Platysma scepincola , it is spoken of as being common in Leight. 
Lich. FI. Ed. 3. According to Nylander, in M. Richard's Cat. 
Lich. Devx Sevr , p. 16, it had not yet been met with in France. 
2. Parmelia aspidota, Ach. 
This is closely allied to the preceding species, of which it has 
generally been regarded as a variety. It is, however, well dis- 
tinguished externally by the papillato — exasperate thallus and 
the verrucoso-papillose margin of the apothecia, while internally 
the medullary reaction with Ca. Cl. is -f , and the spores also are 
smaller and the spermatia longer. It is the Lichen olivaceus of 
