334 Harper.—Sexual Reproduction in Pyronema 
groups in all stages of their development, which leave nothing 
to be desired as to accuracy and detail so far as the surface 
views of the structures are concerned. In the Carpologia 
the Tulasnes described the formation of asexual spores of 
Pyronema. In the paper under consideration, they correct 
this error and assign the earlier described conidial spores 
to Peziza melanoloma which they found frequently associated 
with Pyronema. 
Kihlmann in 1883 ( 19 ) was the first to discover the develop¬ 
ment of ascogenous hyphae from the archicarp (macrocyst) 
of Pyronema , and thus bring the sexual process here into 
line with what Janczewski (1871) had already described for 
Ascobolus. Kihlmann made a very careful study of the form, 
and the account in De Bary’s handbook ( 13 ) is based on 
his work. He concludes, although without very positive 
evidence, that the macrocysts and paracysts of a group arise 
from separate hyphae. He never observed a macrocyst and 
paracyst arising from a single hypha. He describes them 
as arising simultaneously in from six to sixteen pairs in each 
group or rosette. The paracysts are a few longer than 
the macrocysts and about one half as thick. Sometimes 
two conjugating tubes connect with one paracyst. One case 
was observed in which the paracyst was branched, though 
remaining one-celled, and each branch was connected with 
a macrocyst by conjugating tubes. The conjugating pore 
between the paracyst and conjugating tube is 3-4 [jl in 
diameter, and is bounded by strong sutures. He was able, 
by pressure on the paracyst, to cause a flow of protoplasm 
through this pore from the paracyst to the conjugating tube. 
When the pressure is relieved a return flow is set up. 
Kihlmann also finds that the cross-wall at the base of the 
conjugating tube is always formed before the latter fuses with 
the paracyst, so that a direct mixing of the protoplasmic 
contents of the paracyst with that of the macrocyst is impos¬ 
sible. He thinks, however, that a diffusion of dissolved 
substances may take place through this basal wall of the 
conjugating tube, and that thus fertilization may be effected. 
