1 24 ENDOSPOREAE [DYDYMIUM 



b. Sporangia stalked or forming plasmodiocarps ; capilli- 

 tium without vesicles ; spores more or less spinulose — 



a. Sporangia disc-shaped, with dark stalks. 



6. D. Clavus 



b. Sporangia subglobose or effused — 



Stalk and columella dark brown ; stalk opaque and 

 granular. 7. D. melanosyermum 



Stalk olive-brown or orange, translucent, not 

 granular. 8. D. nigripes 



Stalk and columella white or yellowish ; crystals on 

 sporangium-wall scattered or forming a wrinkled 

 crust ; sporangia often forming plasmodiocarps, 

 dehiscing irregularly. 9. D. squamulosum 



Sporangia forming slender plasmodiocarps with 

 scanty lime deposits, dehiscing in a circumcissile 

 manner ; columella none. 10. D. anellus 



Sporangia forming large pulvinate plasmodiocarps, 

 1 to 25 mm. long, dehiscing irregularly ; columella 

 none ; capillitium forming an abundant elastic 

 network. 11. D. Wilczekii 



Stalk short, membranous, pale buff ; crystals on 

 sporangium-wall forming a smooth, thick, 

 deciduous envelope. 13. D. crustaceum 



C Sporangia with orange stalks ; sporangium- wall 

 hyaline ; spores dark brown, closely reticulated. 



12. D. intermedium 



Subgenus 2. — Lepidodermopsis. Sporangium-wall cartila- 

 ginous. 



Stalk and columella orange or orange-brown ; sporan- 

 gium-wall areolated, orange- brown. 



14. D. leoninum 



1. D. difforme Duby Bot, Gall., ii. 858 (1830). Plas- 

 modium colourless or yellow. Sporangia scattered, pulvinate 

 on a broad base or forming irregularly elongated plasmodio- 

 carps, 0*4 to 2 mm. or more long, smooth, white ; sporangium- 

 wall of two layers, the outer a thin eggshell-like crust of 

 densely combined minute crystals of lime, separating from the 

 iridescent membranous inner layer, which is purplish or 

 colourless above, stout and yellowish-brown at the base 

 and thickened at the margin. Columella none. Capilli- 

 tium scanty, consisting of coarse or slender purple or colourless 

 flattened threads, usually broad at the base, branching 

 dichotomously and slender above. Spores dark purple-brown, 

 usually faintly and closely warted, sometimes marked with 



