PHYSARUM.] PHYSARACE.E. 37 



thallus ; sporangium-wall thin, bright grey. Capillitinm delicate, 

 white, reticulate, with threads of unequal breadth, generally 3 to 4, 

 sometimes as much as 12 /x broad, and thicker at the nodes. 

 Spores single, 7 - 5 to 9 ^ in diameter, violet, smooth. 



Hab. On grass and living herbs. Silesia. 



15. B. irregularis Cooke & Ellis, in Grev. 1877, p. 89. Spor- 

 angia subglobose or confluent, finally blackish-brown, scattered, 

 sessile. Spores rough, globose, blackish, 10 /x in diameter. 



Hab. On Jersey pine in a fence. N. Jersey. 



SPECIES EXCLUDED FROM THE GENUS. 



B. coadnata Host. = Fuligo ettipsospora Lister. 

 B. Fuckeliana Rost. = Trichamphora pezizoidea Jungh. 

 B. nodulosa Mass. = Physarum calidris Lister. 

 B. yranulijera Mass. See note under Lepidoderma Carestianum 

 Rost., p. 106. 



Genus 3. PHYSARUM Persoon, inllsteri, Ann. Bot., xv., p. 5 

 (1795). Sporangia stalked, sessile or plasmodiocarps ; sporangium- 

 wall either single or consisting of two more or less separable 

 layers, and containing lime granules distributed in loose or dense 

 clusters or compacted into a crust ; the granules always innate 

 and not in superficial crystals. Stalk consisting of a tube with 

 a membranous wall : it may be empty and the wall contracted 

 and wrinkled with longitudinal folds, either translucent or 

 opaque with deposits of lime in the wall substance ; or the tube 

 may be filled at the base or throughout with refuse matter 

 discharged from the plasmodium ; or the tube may be filled with 

 deposits of lime, giving the stalk a brittle structure with a chalk- 

 like section. Capillitium forming a network of hyaline threads 

 with vesicular expansions containing deposits of lime ( = lime- 

 knots). 



The genus Tilmadoche is described by Ro.stafin.ski (Mori., p. 126) as 

 differing from Physanun in the capillitium forking repeatedly at a 

 narrow angle, and being provided with few and small lime-knots. 

 These characters are too inconstant to be of value in classification. 

 In P. leucopJiOBum FT., which from its abundance affords ample facility 

 for study, we riot unfrequeiitly observe, in a growth sprung from one 

 plasmodium, some sporangia with capillitium characteristic of Ph</- 

 sarum and others of Tilmadoche, completely uniting P. leucophceum Fr. 

 with T. nu tans Rost. T. gyrocephala Rost. (syn. P. polymorphism T&osi.) 

 frequently has capillitium vrith large lime-knots and broad membranous 

 expansions, and the same may be seen in some gatherings of P. rlride 

 Pers. (syn. T. mutabilu Rost.). The type specimens of T. oblong a 

 Rost. and T.'hians Rost. are the same as Physarella inirdbilis Peck, 

 which is distinguished from its allies by well-marked characters of 

 shape and capillitium that fully entitle it to the position of a separate 

 genus. For these reasons the genus Tilmadoche is not retained. 



