10 Rev. W. A. Leighton on British Lichens. 



culate, the apical cell slightly enlarged and dark coloured. 

 Sporidia 8, in narrow asci, linear-oblong, simple, hyaline. 

 Spermogonia (which I have not seen), according to Bornet and 

 Nylander, lateral, tubercular, black; arthrosterigmata articulate; 

 spermatia "ovoides, fort petites" (Bornet), "breviter cylindrica" 

 (Nylander). 



Even in a sterile state, this plant, which has a general resem- 

 blance to Ephebe pubescens, may be distinguished by attention 

 to the regular transverse arrangement of the gonidia, which are 

 also of much larger size than those of that plant, and altogether 

 differently grouped together. The outline of the filaments in 

 Spilonema is uniform, whilst in Ephebe it is crenate or wavy, 

 arising from the minute rugosities or tuberculations of the sur- 

 face corresponding with the internal strata of gonidia. I thought 

 at one time that there was also a chemical distinction, — dilute 

 sulphuric acid turning the old and young filaments of Spilonema 

 to a dark-green colour, whilst in Ephebe the younger branches 

 were coloured green, and the older stems reddish ; but this 

 character did not seem, after experiments on different specimens, 

 to be satisfactorily constant. 



It is to be feared that, at least in some copies of my ' Lich. 

 Brit. Exsic./ specimens of Ephebe pubescens, which grew in the 

 same locality at Barmouth with Spilonema paradoxum, have been 

 inadvertently inserted. 



Plate IV. fig. 7- Extremity of younger branch, magn. 330 times linear, 

 fig. 8. Portion of older stem, magn. 330 times linear, 

 fig. 9. Sporidia, magn. 1200 times linear, 

 fig. 10. Paraphyses. 

 fig. 11. Sterigmata and spermatia, after Bornet and Nylander. 



Ephebe, Fr., Born. 



Thallus filiform, branched, fruticulose ; granula gonima smaller, 

 subtransversely arranged, in little heaps, two, four, or more 

 together. Apothecia endocarpoid, in thickened portions of 

 the thallus. 



Ephebe pubescens, Fr. Thallus blackish brown, slender, cses- 

 pitose, entangled, branched, slightly rugulose. Sporidia 8 in 

 asci, lineari-oblong or subfusiform, 1 -septate, hyaline; para- 

 physes none. 



Ephebe pubescens, Fr. S. O. V. 256 (1825) ; Bornet, in Ann. Sc. Nat. se'r. 3. 

 xviii. 170, t. 7 ; Nyl. Prod. 17, Syn. 90, t. 2. f. 1. & 17-20; Scand. 24 ; 

 L. P. 1!; Moug. & Nestl. 358!; Henpe, 712!; Fellm. Licb. Lapp. 

 Or. 2! 



Summit of Pen-Maen-Mawr, June 1851. Harlech turnpike, 

 at Barmouth, Caernarvonshire, June 185G. Rocks at Dartmoor, 



