126 ENDOSPOREAE [DIDYMIUM 



2. D. quitense Torrend Fl. Myx., p. 150 (1909). Plas- 

 modium ? Sporangia scattered, sessile, hemispherical, 

 depressed, 04 to 0-5 mm. diam., smooth, white ; outer 

 sporangium-wall white, egg-shell-like, separating from the 

 membranous, pale purplish inner wall. Columella none. 

 Capillitium a network of rather stout purplish-brown flexuose 

 threads, equal in thickness throughout. Spores brownish- 

 purple, 13 to 14 /j. diam., marked with warts and minute 

 V-shaped ridges more or less united to form an imperfect 

 reticulation. — Chondrioderma quitense Pat. in Bull. Soc. Myc. 

 Fr., xi. 212 (1895) ? 



Closely allied to D. difforme from which it differs in the flexuose 

 network of the capillitium and in the spores being marked with an 

 imperfect reticulation. 



Hab. On dead leaves. — Ecuador (B.M. slide). 



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

 watery white. Sporangia solitary, forming rounded or 

 irregular almost flat plasmodiocarps, 1 to 12 mm. broad, 

 0-13 mm. thick; sporangium-wall of two layers, the outer 

 consisting of an eggshell-like crust of closely combined 

 large stellate crystals, often extending beyond the broad 

 membranous base of the sporangium, and powdered with 

 free crystals, the inner layer membranous. Columella none. 

 Capillitium profuse, consisting of rigid, dark purplish-brown 

 threads, anastomosing chiefly above and below and attached 

 at either end by colourless slender branches to the 

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

 smooth, 8 to 15 /x diam. — Mass. Mon., 246. Didymium Listeri 

 Mass. I.e., 244. 



PI. 105. — a. sporangia (Lyme Regis) ; b. c. various forms of capillitium and spores , 

 with crystals from the sporangium-wall ; d. capillitium and spores of the type speci- 

 men from Hauenstein, Bohemia ; e. spore. 



This species may be distinguished in the field from D. difforme 

 by the eggshell-like crust being powdered or mealy with loose crystals, 

 while that of D. difforme is quite smooth and almost glossy. D. 

 dubium is abundant in the neighbourhood of Lyme Regis, where it 

 presents considerable variation. In many gatherings the spores are 

 nearly smooth, measuring 8 to 10 /x diam., in others spinulose, 12 to 

 15 fi diam. ; the capillitium may differ from the usual form in being 

 flexuose with bead-like or irregular thickenings and in having short 

 free branches. Specimens submitted to Rostafinski are pronounced by 

 him to differ from the original Hauenstein gathering in having 

 smoother spores and more slender capillitium without thickenings ; 

 considering the variation mentioned above, these characters cannot 

 be accepted as sufficient to mark the Lyme Regis form as a distinct 

 species. This view is confirmed by inspection of part of the type 

 itself, which has kindly been presented to us by Dr. Celakovsky, jun. 



Hab. On rotting leaves, especially on those of ivy and holly. — 

 Lyme Regis, Dorset (B.M. 1327) ; Bohemia (B.M. 2464). 



