LYMAN: STUDIES OF HYMENOMYCETES. 
149 
Schw., P. incrustans B. & C., Daedalea unicolor Bull., Lenzites 
betulina (L.) Fr., Lentodium squamulosum Morg. 
9 
OlDIA. 
Of the twenty-eight species named above, five (all belonging to the 
Polyporaceae) possessed oidia,— viz., Daedalea unicolor, Lenzites 
betulina, Polyporus jumosus, Polystictus conchifer, and Polystictus 
versicolor ; oidia were not seen by the writer in the Hydnaceae although 
Brefeld found them in species of Phlebia and Irpex; nor did they 
appear in the Thelephoraceae. Thus the writer’s results agree with 
those of Brefeld, viz., that oidium formation is present in a large 
proportion of species in the higher families of Hymenomycetes, but 
is not known in the lower familes,— Corticium alutaceum being the 
only known case among the Thelephoraceae, and here the bodies 
produced may more properly be called conidia than oidia (see p. 163). 
The method of formation is well described by Brefeld (’89, p. 25). 
They arise by the division of a hypha into many cells which become 
separated from one another to form thin-walled, short-cylindrical 
bodies with rounded ends and usually with dense refractive contents 
(pi. 18, fig. 1). The retention of vitality by oidia is short, but if 
transferred to drop cultures when fresh they germinate readily in 
case of the species studied by the writer, enlarging greatly in most 
cases, and producing germ tubes at one or both ends. 
Chlamydospores. 
k 
Chlamydospores were produced in abundance in the writer’s 
cultures upon the mycelia of the following species: Lentodium 
squamidosum, whose position is midway between the Agaricaceae 
and the Polyporaceae; Poria incrustans (?) of the Polyporaceae; 
Radidum tomentosum, two undetermined species of Irpex (or Hydnum), 
and one of Phlebia of the Hydnaceae; Corticium vagum and Corticium 
efjuscatum of the Thelephoraceae. Moreover, the spores of Michenera 
artocreas, which is now shown to be an imperfect state of Corticium 
subgiganteum, are chlamydospores of a specialized nature. 
Brefeld (’89) found chlamydospores only in Ptychogaster and 
Fistulina of the Polyporaceae, and in Nyctalis of the Agaricaceae,— 
three genera in which there is a copious formation of chlamydospores 
