352 
Species 1. P. elatina, Acli. (Nyl., Prod., p. 171). 
On apothecia of Lecanora parella and Pertusaria communis 
(= Variolaria amara, Ach.). 
Spores colourless or becoming brown, 4 — 6-locular, 
sometimes becoming sub-muriform, slightly blue with iodine 
— an unusual reaction of the spore in Lichens. 1 
Genus XXXVIII. — Arctoaita, Th. Fries. 
Species 1. A. delicatula, Th. Fr. 
On decayed Lichens in Spitsbergen (L. Spitsb., p. 17). It 
does not appear whether it is really athalline; or merely, 
having a proper thallus, overspreads Lichens, as in Scandi- 
navia it does mosses. 
Very similar to many of the Micro-lichens recorded in the 
foregoing enumeration are certain other very minute or 
microscopic forms, which appear to be athalline or nearly 
so, but which grow on Mosses or Hepaticce, e. g. — 
1. Lecidea contristcins, Nyl. (Flora, 1865; Leight., “ Not. 
Lich./’ Ann. N^t Hist., 1866). 
Discovered by Carroll on decaying Andrece on the summit 
of Ben Lowers (1864). 
2. Verrucaria tristicula , Nyl. (Flora, 1865 ; Leight., 
‘■'Not. Lich.,” Ann. Nat. Hist., 1866). 
Found by Admiral Jones on Weissia, in Aberdeenshire. 
3. V. dubiella, Nyl. (Flora, 1865). 
On mosses, mountains about Loch-na-Cat (Carroll, 1864). 
4. Lecidea Scapanaria, Carrington, Irish Cryptogams, 
p. 8. 
Syn. Dactylospora, Mudd. 
Spores 6 — 8, fusiform, 4-locular, brown. 
5. L. persimilis, var. Scapanaria, Nyl. ; Carrington, Irish 
Crypt., p. 9. 
Parasitic on the stems and leaves of Scapania undidata, v. 
major, and S. cequiloba. Nylander (Scand., 236) describes 
the type as having a proper thallus. 
Spores ellipsoid, 4-locular, brown. 
The foregoing list represents — as I have already explained 
1 Nylander (‘Prod.,’ p. 172) points out that, the epispore of Pyrenula 
uberina. Pee, becomes wine-red with iodine, while the endospore remains 
colourless. I have figured a blue reaction of the epispore in the spores of 
Parmelia ntegaleia, Nyl., in my “ Observations on New Zealand Lichens” 
(‘ Trans. Royal Society of Edin./ vol, xxv, pi. 61, fig. 2 «). 
