PHYSARUM.] PHYSAEACE.E. 37 



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

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

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

 Spores single, 7 '5 to 9 /a in diameter, violet, smooth. 

 ndb. On grass and living herbs. — Silesia. 



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

 angia subglobose or confluent, finally blackish'^rown, scattered, 

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



Hah. On Jersey pine in a fence. — N. Jersey. 



SPECIES EXCLUDED FROM THE GENUS. 



B. coadnata Kost. = Fuligo ellipsospora Lister. 

 B. Fuckeliana Rost. = Trichamphora pezizoidea Jungh. 

 B. noduhsa Mass. = Physarum calidris Lister. 

 B. granulijera Mass. See note under Lepidoderma Garestianum 

 Host., p. 106. 



Genus 3.— PHYSARUM Persoon, inUsteri, 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 Rostafinski (Mon., p. 126) as 

 differing from Physarum in the capillitium forking repeatedly at a 

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

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

 In P. leucophceum Fr., which from its abundance affords ample facility 

 for study, we not unfrequently observe, in a growth sprung from one 

 Plasmodium, some sporangia with capillitium characteristic of Phi/- 

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

 with T. nutans Rost. T. gyrocephala Rost. (syn. P. polymorphum Rost.) 

 frequently has capillitium with large lime-knots and broad membranous 

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

 Pers. (syn. T. mutahilis Rost.). The type specimens of T. ohlonga 

 Rost. and T. hians Rost. are the same as Physarella mirahilis 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. 



