MYXOMYCETKS. 29 



) ) Spores single, free. 



! Sporangium beautifully irides- 

 cent, violet. 



Spores -0125 mm. . . UTEICDLARIS. 

 ! ! Sporangia grey or white ; 



Spores -01J6--014S mm. . macrocarpa. 

 Spores -0125-'015 mm. . ajfinis. 



It will be observed that three British species are not included in 

 this artificial key. 



Genus 11. SCYPHIUM. R. 



Sporangia with a single wall, splitting with a deciduous lid, with 

 the margin slightly lacerated ; capillitium uniformly grown to the 

 walls of the sporangium, its numerous branches combined into an 

 all-sided net, throughout their whole length filled with small 

 granules of lime ; columella either originating with the capillitium 

 or prolonged directly from the stem. Rtfki. lUon., 148. 



27. Scyphium rubiginosum. (Chev.) 



Sporangia globoso-tuibinate, together with the thin stem which 

 is twice as long as the sporangium, red-brown, smooth, slightly 

 shining; columella distinct, cylindrical, stout, dark, being a direct 

 prolongation of the stem ; capillitium strongly developed, whitish; 

 sporangium dehiscing by a delicate deciduous lid ; spores dark- 

 violet, slightly warted, -OJ4--0148 mm. Rtj ki. J/OH., 148. 



On trunks amongst moss. (Fig. 115.) 



Pliysarwn rubiginosum, Chev. Fl. Par., 338 (1826) ; Eng. Fl., 

 v. 315; Cooke Hdbk., iSo. 1137. 



Family 4. DIDYMIACE.E. 



Wall of sporangia single or double, containing lime in the form 

 of crystals, groups of crystals, or single amorphous grains of lime, 

 compacted now and then into a crustaceous mass ; capillitium 

 usually of threads, rarely of tubes, always thin, either violet-colour 

 or uncoloured, equally thick through their entire length ; threads 

 extending from the base of the sporangium, or from the columella 

 to the walls ; either frequently simple, or with a few branches 

 originating at a sharp angle combined into a net ; either smooth or 

 provided with equally coloured thickenings, varying according to 

 the species, but of the same substance ; granules of lime make 

 their appearance only exceptionally in the threads in certain spo- 

 rangia, as a.kind of nionstrucity, and then always in the shape of 

 small crystals ; columella in the greater number of instances 

 strongly developed, shape very diverse, and of very different 

 capacity. In the sessile forms either the much thickened lower 

 part of the sporangium at the base furnished very much throughout 



