I916. Xo. 8. MONOGRAPH OF THE NORWEGIAN PHYSCIACEAE. 81 



seen many shrunk, undeveloped spores, in many apothecia there are only 

 such spores. — The rhizines of the receptacle are rarely wanting, in 

 some thalli they are so well developed as to form a veritable corona 

 around the apothecia (as in Ph. obsatra f. ciliata). 



The p3-cnides are easily overlooked in dark thalli ; they are evidently 

 not ver}' frequent. 



I have seen authentic specimens of the »P//. obscura var. niu/abi/is^ 

 XiLss. = var. orbicularis et virella Th. Fries, which in my opinion is only 

 a slightly developed Ph. lithofea f. sciostra. 



var. lithotodes (Xvl.) Lynge comb, nov 



Physcia lithotodes Nylander Addenda nova. Flora 1875 p. 360. 

 Olivier Lichens d'Europe I (1907I p. 245 (169). 



Physcia obscura var. lithotodes Wainio Adjumenta I (1881) p. 133. 



Thallus orbicular, up to 6 cm. in diam., loosely appressed to the sub- 

 stratum. Habitus pi acodium-like: Laciniae at the circumference 

 stellate, closely contiguous or more or less imbricate, towards the centre 

 indistinct, almost crustaceous. Laciniae 0,3 — i mm. broad, repeatedly 

 palmato-incise or furcate, rounded at their apices, with undulate contours. 

 Thev are slightly convex, esorediate, without isidia or with some scattered 

 short isidia at the margin, at the apices and at the margin with deciduous, 

 spreading, pale cilia, opaque, epruinose. Colour pale or dark grey, 

 moistened greenish, lower side pale at the circumference, otherwise 

 black. Rhizinae dark or even black, thick: 100 — no«. 



Xo amorphous stratum over the thallus. Upper cortex thin, 8 — 15/* 

 thick, at the exterior part dark, otherwise uncoloured. H\'phae moniliform, 

 occasionally growing out over the surface as hair-like emergences. Goni- 

 dia disposed in a continuous stratum under the cortex, sometimes filling 

 up the whole medulla. Lover cortex 25 — 30 ii thick. 



Apothecia very numerous, covering the whole central part of 

 the thallus, orbicular or angular, i — 2 (2,5) mm. in diam. Gonidia den- 

 sely crowded in the margin and under the hypothecium, more scattered 

 within the cortex of the receptacle. Spores 15,7 — 23,7 u long, 9,2 — 

 11// thick (vide infra), on an average slightly broader than in Ph. lithotea 

 The other parts of the apothecia as in Ph. lithotea. 



' Die Flechten, in Untersuch, des Sarekgebirges ; vol. Ill, p. 49. 

 Vid.-Selsk. Skrifter. I. M.-X. Kl. 1916. No. 8. 



