138 Transactions British Mycological Society. 



Radulum molare Fr. {R. membranaceum Bres.) appears to be a 

 form of Corticium conflaens. Raduloid forms have been 

 recorded of other species of Corticium, etc., and similar relations 

 may be found to exist between many forms hitherto recorded 

 as separate entities. 



This variability is a common enough feature in many groups 

 of fungi and renders all the more important the study of their 

 microscopic features, which would seem, on the whole, to be 

 constant. The spore is a most valuable indication, but it is 

 necessary to point out that the spore alone is rarely sufficient, 

 and must be taken in conjunction with other characters. 



The following species now have to be added to the list given 

 in the last Transactions : 



Platygloea Schroet. 



Receptacle homogeneous, waxy, gelatinous, or coriaceous gela- 

 tinous, effused, or more or less rugulose. Hymenium con- 

 tinuous. Basidia cylindrical, erect, transversely septate, sterig- 

 mata long. Spores uncoloured, smooth, obtuse or apiculate, 

 straight or curved, producing sporidiola on germination 

 Growing on wood. 



Platygloea effitsa Schroet., Pilz. Schles. I, p. 3(84. 



Effused, thin, somewhat gelatinous but firm 

 and greyish when fresh, when dry whitish, closely 

 adherent, hymenium pulverulent under the Jens. 

 Basidia elongated, cylindrical, wavy, apex fre- 

 quently incurved and almost circinate, trans- 

 versely 4-septate, 40-50 X 4-5 /Lt. Spores hyaline, 

 smooth, elliptical or ovate, with oblique apiculus, 

 7-8 (-10) X 4-5 /x. Subhymenial hyphae fine, 

 guttulate, 1-2 IX in diameter, arising erect and 

 parallel from a compact, pseudoparenchymatous 

 basal stratum, made up of broader (4-5 /.i) hy- 

 phae. 



X550 On bark of a fallen branch, St. George's Col- 



lege, Weybridge, June, 1918, A. A. P. The habit 

 effusa^'^ of this plant is like that of a Corticium or Seha- 

 cina, but the transversely septate basidia at 

 once distinguish it when looked at under the microscope. 



Corticium bombycinum (Sommerf.) Bres., Hymen. Hung. Kmet. 



p. 47. Thelephora bombycina Sommerf., Flor. Lapp. 



Suppl. p. 284. 

 Irregularly effused, thick, soft, rather separable, often 

 assuming hydnoid forms, margin and subiculum floccose. 



