162 
irregular effused powdery stratum, which does not in any way 
adhere to the surface. This powderiness, as will be seen, hes led 
to serious misconceptions. 
§ 1. MELANCONIUM 
as a bicolor, Ves, System, TOES, Dp. o2,, tabete, 
Beet; 
. Melanconium betiebiiumn: Schmidt §& Kunze, Exsice. no. 
208, 1819. 
Perhaps the most far-reaching mistakes have been made in 
regard to the Melanconia on Birch. The differences between 
M. bicolor, Nees and M. oe Schmidt et Kunze, as stated 
The descriptions of the two species are ven by Link, in 
i Species Plantarum, 1825, ed. iv, vol. 6, pt. 2, front 
he placed them in ieee enera. 
The starting point of the agen poeay: must lie in MZ. bicolor. 
The essential points described by es (l.c.) are that the fungus 
occurred in Oak, and that + ees were ‘‘eyférmig.”’ He 
figures them as distinctly « ovoid, but on the whole not much longer 
than broad. Link (l.c. p 92) ‘does not make the matter chante: 
he describes the spores as rn ieniog oblongisque,”’ and t 
habitat as ‘‘ in ramis ejectis variarum arborum’’; but aa 
he adds the synonym ‘“‘ M. discolor, Schmidt et Kunze exs. n. 
157” (published in 1817). An examination of this exsiccatum 
shows that the spores tend to be distinctly obovoid (rarely subglo- 
bose or oblong), not opaque, with one guttule, and measuring on 
the non 10-12 x 6-8». This agrees with the fungus called 
The other fungus, which seemed to Link to be nistage rede is 
called s him (Ic. p. 94) ee elevatum, Lin 
cites as ‘its type “‘ Melanconium betulinum, Schmid t et tiie: 
exsice. n. 208” (published in 1819), and gives the habitat as 
“ corticibus Betularum et Fagorum emortuis.’”? An examination 
obovoid and a pele Oe or even oblong, but es usually a 
very different ao. from those arieed by Nees. This is 
the fungus called below 0. 2. 
On investigation of the ; deahinleits issued oy. tp ‘mycologists 
