perichaejja] arcyriaceae 247 



Myc, Nachtr. 76 (1873). L. incarnatus Schroet. in Colin 

 Krypt. Fl. Schles., iii. pt. 1, 110 (1885) ; Mass. Mon., 138. 



PI. 183. — a. sporangia ; b. capillitium and spores with fragment of sporangium- 

 wall ; (England). 



The small sporangia of this species are often heaped together to 

 form large hemispherical clusters 5 to 8 mm. across and 3 to 5 mm. 

 thick ; around the larger groups a few isolated sporangia are usually 

 scattered. When freshly formed their colour is pale copper-colour, 

 but this soon fades to dull ochraceous-yellow. The description of 

 Perichaena congesta (Somm.) Fr. applies fairly well to the present species. 

 Fries's account of Arcyria (Lachnobolus) circinans, however, with its 

 large rusty-red sporangia, fugacious sporangium-walls, rust-co loured 

 spores, and compact globose masses of brown capillitium, is not so 

 appropriate, and may possibly refer to a stunted form of A. ferruginea ; 

 but in the absence of the type this must remain conjectural. 



Hab. On dead wood. — Somerset (B.M. 291) ; Epping Forest, Essex 

 (B.M. 3115) ; Haypit, Stafford (B.M. 1519) ; Alderley Edge, Cheshire 

 (B.M. 3116) ; France (Paris Herb.); Brussels (B.M. 3117); Sweden 

 (B.M. 3118) ; Tyrol (Strassb. Herb.) ; Bohemia (B.M. 3119). 



Genus 45.— PERICHAENA Fries Symb. Gaster., 11 (1817). 

 Sporangia subglobose, sessile or forming plasmodiocarps, 

 rarely shortly stalked ; sporangium- wall of two layers 

 (single in P. microspora), the outer thickened with angular 

 granules which are exceptionally absent in the upper part, the 

 inner usually membranous ; capillitium of branching or simple, 

 tubular, inelastic threads, spinose, minutely warted, or nearly 

 smooth, usually marked with irregular constrictions ; spores 

 yellow or brown, minutely warted. 



KEY TO THE SPECIES OF PERICHAENA. 



A. Sporangium- wall firm, double : — 



a. Sporangia brown or grey — • 



Sporangia subglobose or forming plasmodiocarps ; capilli- 

 tium spinose ; spores 8 to 10 ^ diam. 1. P. chrysosperma 



Sporangia flattened ; capillitium minutely warted, abun- 

 dant ; spores 10 to 11 ^ diam. 2. P. depressa 



Sporangia subglobose ; capillitium warted or nearly 

 smooth, usually scanty; spores 11 to 14^. diam. 



3. P. corticalis 



b. Sporangia stalked, purple-red or purple-brown. 



4. P. pulckerrima 



B. Sporangium-wall membranous : — 



Sporangia pale umber or buff ; spores 10 /x diam. 



5. P. vermicularis 

 Sporangia flesh-coloured ; spores 6 p diam. 



6. P. microspora 

 Q 2 



