DIDYMIUM.] 
DIDYMIACEiE. 
99 
capillitium may vary from white to purplish-brown in the same group 
of sporan^ria, and the colour of the stalk and columella is also inconstant. 
The specimen B. M. 885, from Eavenel, S. Carolina, has some 
sporangia with dark brown and others with deep orange . stalks and 
columella on the same leaf, representing the forms a and /3 JJ. 
eximium Peck and D. fulvellum Mass. have orange-red stalks, with the 
columella orange or pale buff. The type of D.i^roximnm Berk & Curt. 
(K 1493) has also orange-red stalks and a buff columella. The type 
of D. iJertusum Berk. (K. 463) has orange stalks and a white columella; 
it corresponds with the description of D. xanthopus of Fries in all 
essential characters, for the shape of the columella referred to by 
Berkeley is a varying feature. D. elegantissimum:M.ass. (K. 1) is the 
same variety. These forms blend into one another so completely that 
they are here united under D. nigripes. 
Hah. On dead leaves.— a. Lynton, Devon (L:B.M.7G) ; a. Lyme 
Eegis, Dorset (L:B.M.76) ; y. Batheaston, Somerset (B. M. 69, 101) ; 
y. Edinbro' (K. 440); a. France (Paris Herb.); Germany, a. & y. 
(Strassb. Herb.) ; ^. (B. M. 436) ; a. Switzerland (B. M. 555) ; y. Sey- 
chelles (Paris Herb.) ; Ceylon, a. (B. M. 561) ; /3. (B. M. 559) ; y. (B. M. 
577) ; y. Australia (B. M. 562) ; /3. New Jersey (B. M. 566; ; y. New 
York (B. M. 564) ; S. Caronila, a. & /3. (B. M. 884, 885) ; y. (B. M. 
857) ; a. Brazil (K. 319) ; a. Chili (Strassb. Herb.). 
7. D. eiFusum Link, Obs., ii., p. 42 (1816). Plasmodium 
greyish-white, among dead leaves. Total height 0'5 to 1 mm. 
Sporangia subgiobose, or hemispherical, umbilicate beneath, 
stipitate, or sessile, or elfused plasmodiocarps, gregarious, snow- 
white from abundant stellate crystals, which often form a 
wrinkled, deciduous, scaly, outer crust, or grey when the crystals 
are more scanty ; in the plasmodiocarp forms the crystals are 
sparsely distributed ; sporangium-wall membranous, sometimes 
mottled with red-brown towards the base. Stalk white, cylindrical, 
deeply furrowed, opaque and granular from deposits of lime, as 
long as the sporangium, or very short or wanting. Columella 
white, hemispherical ; wanting in effused plasmodiocarps. Capil- 
litium variable, of delicate or coarse threads, almost simple, or 
branching at an acute angle, usually with dark or pale calyciform 
thickenings ; colourless, violet, or purplish-brown. Spores violet- 
brown spinulose, 8 to 11 /a diam.— Rost., Mon., p, 163; Mass., 
Mon., p. 236. I), squamulosum Fries, Symb. Gast., p. 19 (1818); 
Rost., Mon., p. 159; Cooke, Myx. Brit., p. 33; Mass., Mon., 
p. 223; Blytt, Bidr. K. Norg., Sop. iii., 1892, p. 6. Diderma 
squamulosum Alb, & Schw. , Consp. Fung. , p. 88 ( 1 805). Didymium 
leiicopus Fries, Syst. Myc, iii., p. 121. D. costatum Fries, I.e., p. 118. 
D. conjluens Rost., Mon., App., p. 22. D. maci-ospermum Rost., 
Mon., p. 161; Mass., Mon., p. 228, D. Fuchelianum Rost., 
Mon,, p, 161; Mass,, Mon., p. 222. D. prcecox de Bary, in 
Rab. Fung. Eur., No, 367 ; Rost., Mon., p. 163 ; Mass., Mon,, 
p, 223. D. radiatum Berk, & Curt., in Journ, Linn. Soc, x,, 
p. 348 ; Mass., Mon,, p. 229 (in part). Chondrioderma Alexan- 
drovnczii Rost,, Mon., p, 169, Didymium Alexandroioiczii Mass,, 
Mon,, p, 232, Chondrioderma Cookci Rost., Mon., App., p. 17. 
