559 
Ascocarp in Lachnea cretea. 
Harper (’10) calls attention to the marked increase in size of the nuclei 
in the ascogonium in connexion with fertilization. In his opinion, judging 
from the size of the nuclei in Claussen’s figures of young ascogenous hyphae, 
their fusion has already taken place. To a certain extent, changes in bulk 
may be accounted for by growth, but growth alone does not explain such 
differences between neighbouring nuclei as are shown by Blackman and 
Fraser (’06) in the ascogonium of Humaria granulata (Figs. 14 , 16 , &c.) or 
by Cutting (’09) in that of Ascophanus carneus (Fig. 9 ). 
Both Claussen and Faull have attached importance to the conjugate 
arrangement of the nuclei in the ascogenous hyphae as indicating that each 
pair represents an associated male and female nucleus. There is no doubt 
that a conjugate arrangement is common in the most diverse parts of certain 
Ascomycetes. It has been described in the last few cells of the ascogenous 
hyphae in a large variety of forms by many authors (Maire, ’03, ’05 ; Brown, 
TO, &c., &c.), by McCubbin (TO) in the vegetative hyphae of Helvetia 
elastica , by Carruthers (’ll) in the paraphyses of Helvetia crispa , by 
Nichols (’96) in the germ tubes of the ascopores of Ceratostoma brevirostre , 
and by Massee (’05) in the conidial mycelium of Hypomyces perniciosum , 
and in some other forms. 
But there is nothing to show that it depends on a previous association 
of sexual nuclei or of their representatives, and in the upper reaches of 
ascogenous hyphae it may well be explained by the prospective fusion 
in the ascus — whatever the significance of that curious process. 
A more critical question is the arrangement in the ascogenous hyphae 
at their first formation. Claussen figures these hyphae in Pyronema as 
multinucleate, the nuclei being arranged more or less regularly in pairs. It 
is very difficult to think of an attraction which, while not strong enough to 
bring about fusion, yet holds a pair of sexual nuclei together in a multinu- 
cleate organ, where, to judge from Claussen’s figures, they may be not even 
in contact and where they may be equally near to members of another pair. 
Such an arrangement seems to the writer to require overwhelming proof. It 
is not at all comparable to that of the Uredineae, where each pair of conjugate 
nuclei is isolated in a separate cell (Maire, ’ll, &c., &c.). In the Mildews, 
where normal fertilization takes place and where the ordinary cells are 
uninucleate, thus making a paired arrangement much easier to detect than 
in coenocytic species, the conjugate condition has not been observed 
(cf. Harper, ’05, p. 19 ). 
It may be noted in this connexion that vegetative nuclear fusions, 
among which that in the developing ascus might well be grouped, have been 
recorded in the cells which give rise to the paraphyses in Leotia (Brown, TO), 
in the young hairs of Lachnea albo-spadicea (Massee, ’97), in the quadri- 
nucleate ascus of Humaria rutilans (Fraser, ’08), and in the conidia of 
Hypomyces (Massee, ’05). The phenomenon of conjugate division is probably 
