diderma] physaracbae 101 



Sporangia mottled, brown ; columella convex, 

 ochraceous ; stalk black. 14. D. roanense 



Sporangia brown, marked with close radiating dark 

 lines, usually sessile, hemispherical ; columella 

 white, covex. 15. D. asteroides 



Sporangia and clavate columella white ; stalk 

 slender, black. 16. D. rugosum 



Sporangia bright orange ; columella clavate or 

 globose ; stalk dark brown. 17. D. lucidum 



Subgenus 1. — Eudiderma : sporangia sessile (or stalked in 

 Nos. 2 and 6) ; sporangium-wall dehiscing irregularly, consist- 

 ing of two layers (except in No. 8), the outer layer a smooth 

 crust of globular lime-granules, the inner layer membranous. 



1. D. subdictyospermum Lister. Plasmodium ? Spor- 

 angia crowded, subglobose or hemispherical, sessile, 03 to 

 0-5 mm. diani., snow-white, seated on a well-developed white 

 hypothallus ; sporangium- wall thick, fragile, composed of an 

 outer crust of globular lime-granules closely adhering to the 

 delicate membranous inner layer. Columella hemispherical or 

 subglobose, white. Capillitium consisting of somewhat rigid 

 purplish sparingly branched threads, anastomosing near the 

 extremities. Spores 10 to 12 p diam., violet-brown, reticulated 

 with raised ridges or with broken bands that form a border 

 about 2 jx broad. — Chondrioderma subdicytospermum Rost. 

 Mon., App. p. 16 (1876) ; Lister Mycetozoa, 77 ; Penzig 

 Myx. Buit., 44. C. dealbatum Mass. Mon., 207 (1892). Didy- 

 mium dealbatum Berk. & Curt, in herb. 



PL 87. — d, sporangia (Venezuela) ; e. capillitium and spores ; /. spores. 



This species appears to be allied to D. spumarioides, but differs 

 essentially in the reticulated spores. The type from Venezuela (B.M. 

 570), marked in Berkeley's herbarium " Didymium dealbatum," 

 remained undescribed until Rostafinski published it as Chondrioderma 

 subdictyospermum ; in this specimen the spores are provided with 

 protuberances either irregularly disposed or combined into an incom- 

 plete net. Two other gatherings have been obtained, one from the 

 Cape, the other from Java ; in these the spores are regularly reticulated 

 with raised bands. 



Hob. On moss and dead leaves. — Cape (K. 466) ; Java (B.M. 2812) ; 

 Venezuela (B.M. 570). 



2. D. hemisphericum Hornem. Fl. Dan., fasc. xxxiii. 

 13 (1829). Plasmodium opaque white. Sporangia scattered, 

 flat, disc-shaped on a central stalk, 1 to 1-25 mm. diam., 

 rarely sessile and confluent, chalk-white ; sporangium-wall 

 of two layers on the flat upper surface, the outer a smooth 

 crust composed of globular lime-granules 1 to 3 p diam., 

 easily separating and breaking away from the more persistent 



G 



