DIDYMIUM.] DIDYMIACE.E. 95 



Mass., Hon., p. 212; Blytt, Bidr. K. Norg., Sop. iii. (1892), p. 6. 

 Didymium Libertianum de Bary, Mycetozoa, p. 124. Diderma 

 liceoides, Fr., Syst. Myc., iii., p. 107. Licea macrospora Schwein., 

 in Trans. Am. Phil. Soc. (1834), p. 258. Chondrioderma liceoides 

 Host., Mon., App., p. 17 ; Mass., Mon., p. 215. 



Plate XXXVII. , A. a. sporangia, x 20 ; b. capillitium attached to the 

 sporangium-wall, which shows the thickened margin of the base passing into 

 the membranous upper wall, x 280 ; c. portion of the crystalline crust of 

 lime, x 280; d. delicate capillitium, x 280; e. spore, x 600 (England). 



This species is removed from Chondrioderma, where it was placed 

 by Rostafinski, on account of the crystalline character of the lime 

 forming the outer crust of the sporangium- wall. It is to be regretted 

 that there is no type of C. calcareum Host, in Strassb, Herb., for the 

 description in Rostafioski's Monograph answers well for the forms 

 of D. difforme with well developed capillitium ; as the latter species is 

 given by Rostafinski as being almost destitute of capillitium, it is 

 possible that C. calcareum is not entitled to specific rank. The type 

 specimen of Chondrioderma liceoides Rost. (K. 1206) from the Schweinitz 

 Herb., marked Licea macrospora by Schweinitz, is Didymium difforh ; 

 the structure of the sporangium-wall and the characters of the capil- 

 litium and spores are quite typical. 



Hab. On dead leaves and herbaceous stems. "Wanstead, Essex 

 (L:B.M.71) ; Welshpool, Montgomery (B. M. 1062) ; France (K. 386) ; 

 Germany (B. M. 507, 521, 524, 529): Belgium (K. 401); Italy 

 (B. M. 527) ; India (K. 1466) ; Seychelles (K. 1467) ; Carolina (K. 1206). 



2. D. dubium Rost., Mon., p. 152 (1875). Plasmodium watery 

 .white, among dead leaves. Sporangia rounded or irregular plas- 

 modiocarps, depressed, solitary, 1 to 12 mm. broad, - 13 mm. 

 thick ; sporangium-wall of two layers, the outer consisting of 

 large stellate crystals combined to form a fragile uneven crust, 

 more or less attached to the delicate membranous inner layer. 

 Coluniella none. Capillitium of profuse, rigid, erect, dark purplish- 

 brown threads, anastomosing chiefly above and below, and at- 

 tached at either end by colourless slender branches to the 

 sporangium-wall. Spores violet-grey, spinulose or nearly smooth, 

 8 to 15 /x diam. Cooke, Myx. Brit., fig. 167 ; Lister, in Journ. 

 Bot. (1891), p. 261 ; Mass., Mon., p. 246. Didymium Listeri 

 Mass., Mon., p. 244. 



Plate XXXVII., B. a. sporangia, x 20 ; b, c, d, e. various forms of 

 capillitium, and spores, x 280 ; /. fragment of sporangium- wall, showing 

 the crystalline outer layer, x 280 ; g. spore, x 600 (England). 



This species is abundant at Lyme Regis, where it presents consider- 

 able variation. In many gatherings the spores are nearly smooth, 

 measuring 8 to 10 /n diam., in others spinulose, 12 to 15 p diam. ; the 

 capillitium may differ from the usual form in being flexuose with 

 bead-like or irregular thickenings and with short free branches. Speci- 

 mens submitted to Rostafinski are pronounced by him t be distinct 

 from the original Hauenstein gathering in having smoother spores and 

 rrtore slender capillitium without thickenings ; considering the varia- 

 tion mentioned above, these distinctions cannot be accepted as sufficient 

 to mark the Lyme Regis form as a distinct species. 



Hab, On dead leaves. Lyme Regis, Dorset (L:B.M.72) 



