Lamproderma columbinum Rosi. and its Varieties. 33 



ravine near Llanymawddwy, North Wales, by Lady Bradford 

 and myself, from Hexham by I\Iiss E. K. Higgins, from Porlock 

 by Mr N. G. Hadden, from Keswick by Mr W. N. Cheesman, 

 from Aberdeenshire by the Rev. W. Cran, from near Berlin by 

 Dr Jahn, from the Vosges mountains by M. Demange and from 

 the Jura by M. Ch. Meylan*. 



The other form has globose sporangia, with either long or 

 short cylindrical stalks, and rather lax flaccid colourless ca- 

 pillitium. A specimen of this having almost sessile sporangia, 

 gathered by Richard Spruce in the P^Tenees in 185 1, was named 

 by Berkeley Physarum iridescensj, and by Rostafinski Lampro- 

 derma iridescensl- It has been found several times in North 

 Wales, usually with long stalks and associated with var. hrevipes. 

 In the field it has the aspect of typical L. columbinum of which 

 it is apparently a weak development. A feature suggesting 

 weakness is that the stalks are not solid below but enclose a 

 loose sponge-like network of interwoven strands. 



In both editions of the British ]\Iuseum Catalogue of Myce- 

 tozoa this form is included under L. columbinum var. sessile 

 Lister. The variety was established to cover an assemblage of 

 doubtful specimens, two of which have proved to be new species 

 belonging to entirely different genera, namely Diachea cerifcra 

 G. Lister and Leptoderma iridescens G. Lister. It would seem 

 well therefore to drop the name sessile, and restore Berkeley's 

 name iridescens for the variety of L. columbinum with colourless 

 capillitium. 



The colour of the plasmodium in this species is usually watery- 

 white, but it may also be opaque-white or yellow. Miss A. M. 

 Da\idson \vrites that in woods near Aberdeen she has observed 

 the form with obovoid sporangia maturing from watery-white 

 Plasmodium "nearly fifty times," and less frequently globose 

 sporangia maturing from opaque-white plasmodium, "like a 

 streak of white enamel paint." Another specimen from the 

 same woods, approaching var. brevipes in capillitium, had 

 "canary yellow plasmodium"; the var. brevipes from North 

 Wales and Keswick had watery- white plasmodium ; typical ovoid 

 sporangia sometimes have plasmodium of a dull yellow colour. 



M. Ch. Meylan has described a new species, L. Cruchetii^, 

 from specimens found on Le Chasseron, Jura Mountains, on 



* It is probable that Lamproderma Staszcii Raciborski (Hedwigia, vol. 28, 

 p. 116 (1886)) from the Tatra Mountains, "Poland," ma}^ be an extreme form 

 of var. brevipes. The sporangia are described as violet-black, on very short 

 stout stalks, with broad flattened capillitium threads, 30^1 wide below, dicho- 

 tomously branched and narrowing above till towards the surface thej' are 

 very slender; spores 12-5 to 15/x. 



t Hooker's Journal of Botany, iii, p. 20 (1851). 



X Monograph of Mycetozoa, Appendix, p. 25 (1876). 



§ Bull. Soc. Vaud. Sc. Nat. no. 52. p. 96 (1918). 



