512 



LICHEXACEI, 



[PHLTCTIS. 



X-250 



Fig. 72, 



Thbjctis agelcBa Koerb. — A. A 2- 

 spored theca and paraphysis, X 

 250. B. Two spores, x350. 



or murali-divided. Spermogones with simple or slightly branched 

 sterigmata. 



Differs from the preceding subtrihe in the apothecia being usually more 

 open, and especially in the spores hem^x muraU-divided. It comprises 7 

 genera, four of which are entirely exotic, while Belonia Koerb., though 

 European, does not occur in Britain. 



64. PHLYCTIS Wallr. Xaturg. 

 der Flecht. (1S25) p. 527.— Thallus 

 thinly crustaceous, continuous or 

 pulverulent. Apothecia rotundato- 

 difForm, usually suffused, erumpent, 

 the thalline margin irregularly 

 dehiscent or indistinct : hypo- 

 thecium colourless ; spores large, 

 l-2na^, ellipsoid or oblong, murali- 

 divided, colourless ; paraphyses 

 slender ; hymenial gelatine scarcely 

 tinged, but the thecag bluish with 

 iodine. Spermogones with simple 

 sterigmata and short, slender, 

 straight sperm atia. 



A small genus the plants belonging 

 to which are, from the appearance of 

 the fructification, readily overlooked. 

 In some respects it approaches Pertit- 

 saria, but is definitely separated by the muriform spores. Of the three 

 Eviropean species two are found in this country. 



1. P. agelaea Koerb. Syst. Lich. Germ. (1855) p. 391. — Thallus 

 effuse or subdeterminate, thin, rugose or smoothish, often subleprose, 

 ■white or greyish-white (K-|- yellow, then deep-red). Apothecia 

 minute, blackish, white- or caesio-suffused ; spores 2n£e (3-4nae), 

 ellipsoid, mucronate at the apices, 0,04.5-70 mm. loug, 0,014-27 

 mm. thick. — Mudd, Man, p. 279, t. 5. f. 118 ; Cromb. Lich, Brit, 

 p, 61 ; Leight, Lich, Fl. p, 246, ed, 3, p, 237. — Thelotrema agelc^a 

 Gray, Xat. Arr, i. p. 494 pro parte. Variolaria agela-a Turn, tk 

 Borr, Lich, Brit, p, 78; Sm. Eng, El, v, p. 171. Lichen agelceus 

 Ach. Prodr, (1798) p. 30; Eng. Bot, t, 1730, Variolaria con- 

 stellata Tayl. in Mack, Fl. Hib, ii. p. 113 pro parte (ex specimine 

 ab ipso), — Brit. Exs. : Leight. n. 282 ; Mudd, n. 269. 



Occasionally speads very extensively and then covers the lower portion 

 of the trunks of trees. The apothecia, which are scattered or more 

 fi-equently crowded, are at first entirelv enclosed in thalline verruca} and 

 at length leproso-coronate or almost covered by the thallus. The spermo- 

 gonesare very seldom visible in the Britisli specimens. 



Hab. On trunks of trees in maritime and upland situations. — Distr. 

 General and common in England; scarce in S. Ireland; not seen from 

 Scotland or the Channel Islands. — B. M. : Ickworth, Suffolk ; near 

 Yarmouth, Norfolk ; Eppiug Forest, Quendon, and IJickling, Essex ; 

 Penshurst, Kent : Shiere, Surrey; Glynde and Hentield; Sussex ; Cai'is- 



