46 ENDOSPOKE.E. [PHYSARUM. 



:uid densely charged with calcareous deposits. Stalk coarsely 

 wrinkled, purple-brown. Columella none. Capillitium of delicate, 

 branching, violet threads, with numerous large, angular, purple 

 lime-knots. Spores dark purple-brown, rough with irregularly 

 scattered warts 8-10 /x, diam. 



Plate XVII., B. a. stalked and sessile sporangia, x 20 ; b. capillitium and 

 spores, x 280 ; c. spore, x 600 (Colorado). 



The shape of the sporangia and the dark rough spores appear to 

 be the only points which distinguish this species from Oraterium 

 rubescens Rex, with which it agrees in colour, in the character of the 

 capillitium, and in the structure of the sporangium- wall. 



Hab. On sticks, on mountain, Colorado (B. M. 1014). 



13. P. psittacinum Ditm., in Sturm, Deutsch. Fl., Pilze, 

 p. 125, t. 62 (1817). Plasmodium orange, in the substance of 

 rotten wood. Total height 1 mm. Sporangia globose or somewhat 

 depressed, stipitate, gregarious, 0'5 to 0*8 mm. diarn., purplish- 

 blue mottled with red, iridescent ; sporangium -wall hyaline, deli- 

 cately membranous, sprinkled with orange spots of thicker, more 

 or less granular substance. Stalk equal, erect or curved, furrowed 

 and rugose, vermilion or orange-red, intense clear orange in 

 mountings in glycerine, without deposits of lime, rising from a 

 well-developed hypothallus of the same colour, 0'5 to 0*7 mm. 

 long, O'l mm. thick. Columella none. Capillitium a close 

 network of flat, arching, colourless or yellowish threads, broad at 

 the axils; lime-knots numerous, varying in size, sharply angular, 

 often branching, or confluent in the centre of the sporangium, 

 bright orange, obscurely granular or translucent. Spores fuli- 

 ginous-violet, smooth or nearly so, 7 to 8 /x diam. Eost., Mon., 

 p. 104, figs. 75, 76; Lister in Journ. Bot. 1891, p. 257, PI. 

 308, fig. 1 ; Mass., Mon., p. 274. P. Carlylei Mass., Mon., p. 293. 



Plate XL, B. a. sporangia, x 20 ; I. capillitium with fragment of spor- 

 angium-wall showing crystalline discs, x 280 ; c. spore, x (100 (England). 



The specimens in the Kew collection named Didymium erythrinum 

 Berk, and D. Ravcnelii Berk. & Curt., given by Rostafinski as synonyms 

 of P. psittacinum, must be referred to P. pulchripes. The type speci- 

 mens of P. psittacinum in the Strassburg collection are of the form 

 described above. The type specimen of P. Carlylei Mass. (K. 68) is 

 normal P. psittacinum. In glycerine mountings, flattened disc-shaped 

 crystalline bodies with radiating structure are usually seen imbedded 

 in the sporangium-wall, as in P. virescetis var. gcnui/ia. 



Hab. On dead wood. Germany (B. M. 1109); Poland (Strassb. 

 Herb.) ; New York (K. 1206) ; Carlisle (K. 68) ; Lyme Regis, Dorset 

 (L:B.M.22). 



14. P. viride Pers.,in Usteri, Ann. Bot., xv., p. 6 (1795). Plas- 

 modium yellow, in rotten wood. Total height 1 mm. Sporangia 

 globose, lenticular, stipitate, nodding, 0*3 to 0*5 mm. diam., yellow, 

 greenish, or orange ; sporangium- wall membranous with innate 

 clusters of yellow or orange lime-granules more or less closely 

 disposed. Stalk subulate, slender, striate, grey or straw-coloured, 

 often darker below from enclosed refuse matter, wit!. out deposits 



