56 Transactions British Mycological Society. 
remains unchanged. The flat mucous forms are therefore in- 
dissolubly linked up with the coriaceous Sebacinas, and there 
is no point where a division could be made. 
SEBACINA FUGACISSIMA Bourd. et Galz. in Bull. Soc. Myc. Fr. 
XXV, 1909, p. 28. 
Effused in a very thin mucous hyaline greyish film, which 
disappears completely on drying or leaves only a slightly 
glistening trace barely visible sub lente. Hyphae 2-3 p; basidia 
longitudinally septate 6-7 x 5-6. Spores hyaline, cylindrical 
curved 44-7 x 24-4). 
Horsley, Feb. 1920 and Feb. 1921. On crumbling wood in 
the last stage of decay. 
Since the original description of Sebacina fugacissima numerous 
gatherings have shown the species to be very variable. Some 
forms are less fugacious than others and the film may vary in 
thickness, but the structure is the same in all. There is, how- 
ever, considerable difference in the spore. The commonest is 
44-5 x 34-4. The type is 6-7 x 24-34. Others are 6-7 x 
2-24 and 6 x 4uy. 
There are other closely allied forms with larger spores, to 
which specific names have been given. It is difficult to define 
the limits and the value of these forms. The only certain fact 
is that they constitute a long and almost uninterrupted series. 
CORTICIUM SPHAEROSPORUM (R. Maire) v. Hohn. et Litsch. in 
Sitzungsbericht. K. Akad. Wiss. Wien, CXVII, I, p. I105, 
1908 (= Hypochnus sphaerosporus R. Maire). 
Thinly effused, arachnoid and porous under the lens, edge 
indeterminate; chalk white, sometimes with a yellow tinge; 
hyphae 2-4 thin-walled with clamp connections; basidia 
clavate 9-15 x 4-6 with 2 or 4 sterigmata 2-44 p long; spores 
hyaline subglobose or obovate, I-guttulate, minutely warted 
with angular warts. 3-6 x 24-4p (mostly 44 x 4y). 
Very like Cortictum confine Bourd. et Galz. in the arachnoid 
strands covering the hymenium here and there, but easily dis- 
tinguished by the verrucose spores. 
Epping Forest, Oct. 1920 on beech log; Horsley, Feb. 1921 
on oak stump. 
CoRTICIUM SUBMUTABILE v. Hohn. et Litsch. Op. cit. CXvI, 
1907, p. 822. 
Effused in a very thin pulverulent membrane, pale cream, 
sometimes with a deeper tint, edge similar; hyphae 1-3 » thin 
walled, septate-nodulose, rarely distinct (no clamp connections 
observed) ; basidia clavate 8-12 x 4-41. with 2 or 4 straight 
