dianema] margaritaceae 257 



(B.M. 3148) : Luton, Beds (B.M. 3149) ; Witley, Surrey (B.M. 3150) ; 

 Epping Forest, Essex (B.M. 3151) ; Norfolk (B.M. 3152) ; Birmingham 

 (B.M. 1535) ; Salop (B.M. 3153) ; Yorks (B.M. 3154) ; Xorth Wales 

 (B.M. 3155) ; Aberdeen (B.M. 3156) ; Norway (B.M. slide) ; Jura, 

 Switzerland (B.M. 3157) ; Portugal (B.M. 3158) ; Japan (B.M. 3159) ; 

 Chocorua, New Hants (B.M. 3160); Punta Arenas, Chili (B.M. 3200). 



Genus 47. DIANEMA Rex in Proc. Acad. Nat. Sci. Phil.. 

 1891, 397. Sporangia sessile, or forming plasmodiocarps ; 

 sporangium-wall membranous or cartilaginous ; capillitium 

 consisting of nearly straight slender threads, attached above 

 and below to the sporangium- wall. 



KEY TO THE SPECIES OF DIANEMA. 



A. Sporangium-wall translucent, membranous ; spores free : — 



Capillitium threads nearly simple, attached to the sporan- 

 gium-wall by short branches. 1. D. Harveyi 



Plasmodiocarps ; capillitium threads attached by acumi- 

 nate extremities to the sporangium-wall. 



2. D. depressum 



B. Plasmodiocarps with cartilaginous walls ; spores clustered. 



3. D. corticatum 



1. D. Harveyi Rex I.e. Plasmodium ? Sporangia soli- 

 tary or in small clusters, sessile, subglobose, hemispherical or 

 cushion-shaped, flattened above, 0-5 to 2 mm. diam., 0*35 to 

 1 mm. in height, sometimes elongated and bent into an 

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

 a metallic lustre ; sporangium-wall membranous, thin, trans- 

 lucent, pale purplish or olivaceous, marked 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 /a diam., simple or sparingly branched 

 and anastomosing, often dividing into slender branchlets at 

 their origin or insertion, nearly parallel, straight or flexuose, 

 running from the base to the upper wall of the sporan- 

 gium. Spores in mass brick-red, dull pink or brownish- yellow, 

 when magnified pale yellow, minutely warted, 8 to 10 /* 

 diam. — Macbride N. Am. Slime-Moulds, 180 ; Torrend Fl. 

 Myx., 84. 



PI. 191. — a. sporangia ; b. capillitium showing attachment above and below to the 

 sporangium-walls, with spores ; c. spore ; (Devon). 



The specimen figured is taken from one of a series of gatherings 

 made in a sheltered valley by the sea near Lyme Regis. They agree 



