PETALONEMA. 237 



2. SCYTONEMA MYOCHROUS Ag. 



Plate LXVIII. Fig. 2. 



Char. Filaments of less considerable diameter, elongate, mostly 

 decumbent and flexuous. 



Lyngb. t. 297. and ocellatum Lyngb. t. 28. Conf. 

 myochrous Dillw. Conf. 1. 19. ; E. B. t. 1555. Conf. mi- 

 rabilis, E. B. 2219. (not of Dillw.) Scytonema con- 

 textum Carmichael. 



Hab. Various parts of Wales : Mr. Dillwyn and Mr. 

 Woods. Neighbourhood of Bantry : Miss Hutchins. 

 Crowborough Warren, and in Pressbridge Warren, near 

 Wych Cross : Mr. Jenner. Dolgelly : Mr. Ralfs. 



This species differs from the previous one only in being 

 smaller in all its parts. I have no doubt of the correctness 

 of Scyt. contextum as a synonym, having, through the kind- 

 ness of Mr. Harvey, had an opportunity of examining an 

 authentic specimen. Carmichael thus describes it : " Thi- 

 species occurs in a thin, closely matted blackish fleece, of ins 

 determinate extent. Filaments two or three lines in length, 

 simple, or rarely furnished with one or two branches," 

 (which are occasionally geminate, as in S. myochrous}, " in- 

 terwoven into an almost inextricable stratum. Sporidia, when 

 visible, which rarely happens, globular and rather distant. 

 Besides the comparative shortness of the filaments, and the 

 more intimate contexture of the stratum, this species differs 

 from S. myochrous in becoming, when dry, of a light greyish- 

 green colour instead of black." Carm. MSS. 



25. PETALONEMA Berk. 



Char. Frond composed of flat, branched or simple filaments, 



the margins membranaceous and striate. 

 Derivation. From irsraKov, a leaf or lamina, and wjjta, a 

 thread ; in allusion to the singularly winged filaments. 



