402 
HARRY M. FITZPATRICK 
ing four nuclei are found. The position of the nuclei in the cell in 
such a case indicates, however, that conjugate division has recently 
taken place, the intervening septum having not yet formed. The 
rarity of these four-nucleate cells shows that the septum is laid down 
rapidly immediately after the completion of the mitosis. The hyphae 
in all parts of the host from the stolons to the tips of the branches have 
been given critical examination, and in all the material studied the cells 
are undoubtedly binucleate throughout. Branches from infected 
plants have been placed in the fixing solution at all seasons of the year, 
but no variation from the binucleate condition has been observed. If 
uninucleate or multinucleate cells occur in the endophytic mycelium., 
they must be present in early stages immediately following infection. 
No material showing these early infection stages has been collected. 
The failure of the writer (12) to obtain infection has, consequently, 
rendered impossible the determination of the point of origin of the 
binucleate condition. 
The two nuclei in any given cell are of practically the same size. 
Those in different hyphae, and in different cells of the same hypha, 
vary considerably in diameter. None of the nuclei in the endophytic 
hyphae reach the large dimensions of certain of those in the interior of 
the sporophore. They are, therefore, less favorable for study of con- 
jugate division. In fact, none of the details of mitosis have been 
clearly observed in the hyphae in the host cells. 
The Sporophore 
The binucleate condition is maintained in all the cells of the hyphae 
composing the sporophore (figs. 5-16). Uninucleate or multinu- 
cleate cells have never been observed. The nuclear pairs divide in all 
cases by conjugate division, and the daughter nuclei are soon separated 
by the formation of transverse septa. The two nuclei of any pair are 
of practically the same diameter, but great difference in size is evident 
between nuclei of different cells (figs. 5,6). The greatest variation also 
exists in the diameter of the hyphae and in the length of the cells. 
In general, the hyphae lying near the center of the sporophore are of 
larger diameter than those near the periphery. 
The variation in size of the nuclei in the cells of the sporophore is 
remarkable. Some of these reach a diameter nearly as great as that 
of the fusion nucleus of the basidium, while others in adjacent hyphae 
are more minute than the nuclei of the spores. It is difficult to explain 
