Lutman—Life History and Cytology of the Smuts. 1223 
rule. In the promycelial cells of the species of Ustilago of the 
cereal grains, the nuclei travel toward each other, come to lie in 
the same cell, and occasionally fuse. In U. antherarum, as 
described by Harper (22), the nucleus of each conidium re¬ 
mains in its place and all that occurs between the conidia is a 
cytoplasmic fusion. Dangeard (12) has probably described a 
similar case in Tilletia where the cytoplasmic fusion of the 
conidia is never followed by a nuclear one. In addition to these 
cases where fusions of various sorts occur, there are probably 
numerous others, where no conjugation of any kind, cytoplasmic 
or nuclear, takes place between either conidial or promycelial 
cells. 
The haustoria constitute another feature in which the two 
groups of the smuts are unlike. The Ustilagos apparently get 
sufficient nourishment from their host plants by occupying in¬ 
tercellular spaces and perhaps by occasionally passing through a 
host cell. It is true that they usually live in positions that are 
favorable for the collection of food materials such as the grow¬ 
ing points of young seedlings, in the ovaries or stamens, etc. 
The smuts of the Tilletia group, on the other hand, have well 
developed haustoria in three species at least;-—Hrocystis 
Anemones, Entyloma Hymphaeae, and Doassansia deformans. 
So far as I have found in the literature the only species hitherto 
known to have haustoria was E. Hymphaeae in which they had 
been described by Raciborski. In all the species in which haus¬ 
toria have been found the smut occurs in tissues less favorable 
for furnishing a concentrated food supply, i. e. in the leaves and 
stems. The intercellular spaces here are large and the smut has 
to develop organs that will actually penetrate the cells and thus 
come in direct contact with the protoplasts. 
The development of the haustoria of Entyloma Hymphaeae is 
of special interest as bearing on the nature of the haustorium 
not only in this group but in the mildews. As has been des¬ 
cribed, the young haustorium originates as a side branch which 
fastens itself to the cell wall and there for a time appears as an 
appressorium, serving apparently as an organ of attachment. 
Soon, however, it sends a tube down into the cell which func¬ 
tions actively as a sucker. Originally perhaps, the appressoria 
