LAMPRODERMA.] STEMONITACE^E. 125 



SPECIES EXCLUDED FROM THE GENUS. 



E. muscorum Lev. = Lamj)roderma irideum Mass. 



Genus 18. LAMPRODERMA Kostafinski, Versuch, p. 7 

 (1873). Sporangia stalked, globose or ellipsoid ; sporangium-wall 

 membranous, somewhat persistent, shining with iridescent colours ; 

 stalk black ; columella cylindrical or clavate, reaching to half or 

 more than half the height of the sporangium ; capillitium con- 

 sisting of branched anastomosing threads, radiating from the 

 upper part of the columella. 



KEY TO THE SPECIES OF LAMPRODERMA. 



A. Total height 2 to 3 mm. 



Capillitium purplish throughout, spores spinulose, 10 to 13 //,. 



1. L. physar aides 

 Capillitium black or grey, spores echinulate, 15 to 20 //,. 



2. L. echinulatum 



B. Total height 1 to 1'5 mm. 



a. Columella branching at the apex. 3. L. arcyrionema 



b. Columella obtuse or truncate. 



Threads of capillitium dark, pale at the base. 



4. L. irideum 



Threads of capillitium dark or pale, not paler at the base. 



5. L. violaceum 



1. L. physaroides Host., Mon., p. 202 (1875), and App., p. 25. 

 Plasmodium ? Total height 2 to 3 mm. Sporangia globose or 

 ellipsoid, stipitate, erect, rarely sessile, gregarious, 0'5 to 0-8 mm. 

 diarn., purplish-black with broken iridescent reflections, or shining 

 like burnished brass ; sporangium-wall membranous, persistent, 

 purplish in the lower part, usually mottled with darker shades. 

 Stalk cylindrical, usually T5 mm. high, 0-15 mm. thick, purplish- 

 black, shining, longitudinally striate or rugose, rising from a dark 

 purplish hypothallus. Columella cylindrical with a conical apex, 

 or clavate, reaching to more than half the height of the spor- 

 angium. Capillitium of purple-brown threads, rarely pale, 

 radiating chiefly from the upper part of the columella, sparingly 

 forked and anastomosing ; towards the surface branching and 

 forming a delicate, nearly colourless network. Spores purple - 

 grey, closely spinulose, 11 to 14 //, diam. Cooke, Myx. Brit., p. 49 ; 

 Blytt, Bidr. K. Norg., Sop. iii. (1892), p. 7 ; Mass., Mon., p. 103. 

 Stemonitis physaroides Alb. & Schw., Consp. Fung., p. 103 (1805). 

 Physarum columbinum Pers., Obs. Myc., i.. p. 5. Lamproderma 

 columbinum Host., Versuch, p. 7 \ in Fuckel, Symb., Nachtr, p. 69 ; 

 Mon., p. 203 ; Mass., Mon., p. 100. Physarum iridescens Berk., 

 in Hook. Journ. (1851), p. 20. Lamproderma iridescens Host., 

 Mon., App., p. 25. 



