8 
A MONOGRAPH OP THE BRITISH HYPOMYCES. 
from those of the other members of the genus. They are formed 
of very large polygonal cells, which become elongated and parallel 
where they form the ostiolum. The conidial state of this fungus 
has been known in this county since the time of Sowerby, but it 
was only in the month of September, 1880, that I was fortunate 
enough to meet with perithecia. Several specimens were then 
found in Hockering Wood in company with the Rev. J. M. Du Port. 
Their development was carefully watched by placing them attached 
to the matrix ( Russula nigricans) upon damp sand under a bell 
glass. The conidia specially affect the pileus of the Nyctalis , often 
so freely as to arrest the growth of the plant, and to cause it to 
assume the appearance of an Onygena. The microconidia are pro- 
duced by the tips of the hyphse, which break off in little cylindrical 
bodies. Lower down upon the same hyphse the macroconidia are 
produced often in great profusion. The lowest portions of the 
hyphas are dilated and convoluted, and it is by an intertwining of 
these convolute bases that the perithecia are produced, pi. 147 d. 
As was the case with Hypomyces chrysospermus, too free a produc- 
tion of macroconidia is unfavourable to the development of peri- 
thecia. These are most frequently found upon or inside the stem 
of the Nyctalis , but they are by no means of common occurrence. 
Plate 147. a. Nyctalis bearing the parasite. Nat. size. 
b. Macroconidia X 400. 
c. Microconidia x 400. 
d. Perithecium in formation x 100. 
e. Perithecium x 10. 
f. Perithecium x 400. 
g. Asci and sporidia (after Tulasne) X 400. 
h. Sporidia x 400. 
ON THE HETERGECISM OF THE UREDINES. 
In a recent number of “Grevillea ” a number of experiments 
performed by the writer upon the alternation of generation of 
Puccinia grammis with JEcidium berberidis were detailed. It will 
be remembered that so frequently were the check plants affected 
with Uredo that the obvious conclusion arrived at was that the 
sEcidium had very little to do with its production. This year 
another series of cultures was instituted, in which the promycelium 
spores of Puccinia granimis were sown upon young barberry plants 
with the unvarying result of producing the ALcidium , the check 
plants remaining free from the fungus. Young wheat plants, which 
were kept continuously covered by bell glasses from the time they 
were first sown till the experiment was concluded, were also found, 
when infected with ripe Azcidium berberidis spores, to become in- 
fected with Uredo , while similar plants not so infected remained 
healthy. But several other species of hetercecismal Uredines were 
