204 ENDOSPORE.E. [DIANEMA. 



Genus 41. DIANEMA Rex, in Proc. Acad. Nat. Sc. Phil., 

 p. 397 (1891). Sporangia simple, often forming plasmodiocarps, 

 depressed, sporangium-wall membranous, without lime ; capillitium 

 abundant, of nearly straight threads without spiral thickenings, 

 attached at both ends to the sporangium- wall. 



KEY TO THE SPECIES OF DIANEMA. 



Sporangium -wall translucent, spores free- 

 Spores minutely warted. 1. D. Harveyi 

 Spores reticulated. 2. D. dejyressum 



Sporangium-wall granular, spores clustered, minutely warted 



3. D. corticatum 



1. D. Harveyi Rex, I.e. Plasmodium ? Sporangia sessile, 

 rounded or cushion-shaped, flattened above, averaging 1 mm. in 

 diarn., O35 mm. in height, sometimes elongated and bent into an 

 irregular horse-shoe shape, dull red or gold-bronze, with a metallic 

 lustre ; sporangium-wall membranous, thin, translucent, beset 

 with the persistent ends of the capillitium when the rest of the 

 threads have broken away. Capillitium of numerous slender, 

 brownish-yellow threads, 1*5 to 2 //, diam., not connected with 

 each other, simple or sparingly branched, forked two or three 

 times near their origin or insertion, nearly parallel, straight or 

 flexuose, running from the base to the upper wall of the 

 sporangium. Spores pale yellow, minutely warted 8 to 10 //, diam. 



Plate LXXIV., A. a. sporangia, x 20; J. capillitium, showing attachment 

 of the threads to the base and upper wall of the sporangium, and spores, 

 x 280 ; c. spores, x 600 (England). 



The specimen figured is taken from a gathering of eighteen sporangia 

 on an ash stick near Lyme Regis, in the spring of 1894. They agree 

 with the type from America in capillitium and spores, but the colour 

 of the sporangia is dull brick-red. By the light of these specimens, 

 that in Broome's Collection (B. M. 94) marked Physarum metallicum, 

 is clearly the same species ; it is in a fragile condition, and as the 

 capillitium breaks up when mounted, the characters are difficult to 

 recognise ; but the numerous broken points of attachment to the base 

 and upper wall of the sporangium, together with the minutely warted 

 spores, leave no doubt of its identity. The date and locality are 

 not given by Broome, but it is probable that it was gathered at 

 Batheaston in 1869 or 1870, as it stands in his collection among other 

 specimens correctly marked Physarum metallicum gathered there at 

 that date. 



Hob. On dead wood. Lyme Regis, Dorset (L:B.M.168) ; Maine 

 (L:B.M.168 slide). 



2. D. depressum Lister. Plasmodium white, rarely rosy red, in 

 rotten apple logs, ash sticks, etc. Sporangia forming sessile, 

 pulvinate, depressed, broad plasmodiocarps, 2 to 10 mm. wide, 

 about 0'3 mm. thick, when immature shining violet, ripening to 

 grey -brown ; sporangium-wall a smooth, translucent, yellowish- 

 grey membrane, beset with the persistent ends of the capillitium 

 when the rest of the threads have fallen away. Capillitium 



