LEPIDODEEMA.] DIBTMIACEjE. 1"^ 



of the sporangia or continued into the capillitium threads. 

 Spores dull purple, strongly spinulous, 10 to 13 ju, diam. — Eost., 

 Mon., p. 191 ; Oooke, Myx. Brit., p. 45 ; Blytt., Bidr. K. Norg., 

 Sop. iii. (1892), p. 7; Macbride, in Bull. Nat. Hist. Iowa, ii., 

 p. 144. Eeticularia alba Bull., Champ., p. 92, t. 326 (1791). 



Plate XLI., A.—as. aethalium, x 2 ; i>. cluster of sporangia from an 

 sethalium ; in three places they are broken and show the hollow columeUs, 

 X 20 ; c. capiUitium and spores, x 280 ; d. crystals from the investing 

 covering of lime, x 280 ; e. spore, x 600 (England). 



Allied to Didymium through D. crustaceum, but separated by its 

 aethalial habit. 



Hah. On grass, dead leaves, etc. Common in Europe. Highgate, 

 Middlesex (B. M. 161) ; Batheaston, Somerset (B. M. 171) ; Oxford- 

 shire (B. M. 1083, 1084, 1086) ; Cromarty, Scotland (B. M. 1088) ; 

 Ireland (K. 684) ; France (B. M. 997) ; Belgium (B. M. 594) ; Germany 

 (B. M. 599) ; Finland (B. M. 697) ; Poland (Strassb. Herb.), Ohio 

 (L:B.M.79); Iowa (L:B.M.79). 



The description of Spumaria Micheneri Berk., in G-rev., vol. ii., p. 52, 

 is too brief in the absence of the type to be of value. 



Genus 14.— LEPIDODERMA de Bary, in Eost., Versuch, p. 13 

 (1873). Sporangia stalked, sessile, or plasmodiocarps ; sporangium- 

 wall cartilaginous, beset with superficial crystalline scales ; capil- 

 litium profuse, without lime. 



KEY TO THE SPECIES OF LEPIDODEEMA. 



Sporangia subglobose . . . . L. 



Sporangia forming plasmodiocarps . L. Ga/restia/num. 



1. L. tigrinum Eost., Versuch., p. 13 (1873). — Plasmodium 

 yellow (teste Schroeter). Sporangia subglobose, flattened and 

 umbilicate beneath, stipitate or sessile, scattered, 1 to 1'5 mm. 

 diam., olive- or purplish-grey, glossy, more or less closely beset 

 with rounded or angular crystalline scales of lime, which are 

 sometimes wanting; sporangium-wall cartilaginous, of two 

 closely combined layers, orange-yellow. Stalk stout, cylindrical 

 0"2 to 0"4 mm. thick, furrowed, orange-brown, of a spongy texture 

 within, containing deposits of lime ; rising from a hypothallus 

 which is either vein-like, or eilused and of a loose reticulated 

 structure. Columella hemispherical, brown, of the same texture 

 as the stalk, containing deposits of lime in rounded nodules. 

 Capillitium profuse, of straight or flexuose threads, sparingly 

 branched, dark purple-brown or grey. Spores dark purplish- 

 grey, mintitely and closely spinulose, 8 to 13 /i diam. — Mon., 

 p. 187; Cooke, Myx. Brit., p. 44; Blytt, Bidr. K. Norg., 

 Sop. iii., 1892, p. 7 ; Mass.-, Mon., p. 253. Didymium tigrinwm 

 Schrad., Nov. Gen. PI., p. 22 (1797). Lepidodermafulvvm Mass., 

 Mon., p. 253. 



Plate XLI., B. — a. sporangium, x 20 ; J. fragment of sporangium- wall 

 with crystalline discs, x 50 ; c. capillitium and spores, x 280 ; d, spore, 

 X 600 (Germany). 



