44 
Blackman and Fraser . — Further Studies on the 
nuclei were not to be seen in Puccinia Adoxae and Uromyces Scillarum , 
and, as far as observations go, seem only to occur in connexion with 
such a transition process. 
General Conclusions. 
The conjugate nuclear condition of the fertile cells (basidia of older 
authors) of the aecidium is mainly the result of one of two processes. 
In the one case, there is a process of nuclear migration from a vegetative 
cell into a fertile cell (female cell) ; this has been observed in Uromyces 
Poae and Puccinia Poarum , as well as in Phragmidium violaceum , where 
it was first described (1). In the other case the fertile cells fuse in pairs, 
and thus the conjugate nuclear condition arises ; this process was first 
observed by Christman (4) in Phragmidium speciosum , Caeoma nitens , 
and Uromyces Caladii , and is described for Melampsora Rostrupi in 
the present paper. 
These two processes are to be considered as merely two different 
types of reduced fertilization which have replaced the normal fertilization 
in the absence of the normal male cells (spermatia). In the one case 
the female cell fuses (partially) with a vegetative cell, in the other case 
two female cells fuse together (vide supra, p. 36). 
While in U. Poae nuclear migration seems to take place only into 
the fertile cells of the aecidium, in Puc . Poarum a small number of 
migrations appear to take place between vegetative hyphae also, either 
below the layer of fertile cells or before such cells have become differentiated. 
The conjugate nuclear condition in these cases is thus started before 
the differentiation of the cells which represent the female cells. 
The basal cells of the aecidium may thus arise by the fertilization of 
a fertile (female) cell by a vegetative cell, by the conjugation of two fertile 
(female) cells or (rarely) as the product of an undifferentiated vegetative 
cell which has earlier undergone a process of fertilization. 
This condition, described in the case of Puc. Poarum , leads on very easily 
to that found in Puc. Malvacearum , where there are no female cells, and the 
change to the conjugate nuclear condition takes place at a different point 
in the life-cycle, without the development of any specially differentiated 
structures, being found only in connexion with the vegetative hyphae, just 
before the formation of the teleutospores. From this point it is a short 
step to the condition found in other forms ( Puccinia Adoxae , Uromyces 
Scillarum ), where the simple and reduced fertilization process takes place 
at some earlier point in the life-cycle without apparent relation to the 
development of the teleutospores. 
It is easy to understand that directly the primitive and £ external ’ 
