The Uredinece. 
»37 
The Formation of the Promycelium. 
According to Harper and Holden the fusion nucleus divides 
and the now elongated teleutospore divides, each daughter cell 
receiving one of the daughter nuclei. Each daughter nucleus now 
divides as above and the teleutospore has now grown into a four- 
celled promycelium, each cell of which contains a single nucleus, 
the four internal basidia are arranged one above the other and 
looking like a four-celled spore, each hasidium gives rise to a 
pedicelled two-nucleated spore, the so-called sporidium. This is 
the usual and typical condition in most of the forms studied (Arthur) 
(Harper and Holden, Fig. 6). In Coleosporium sp. on Ventouia and 
on Anemone , the latter forming the subject for the present study, 
the details of the division relative to the formation of the promycelium 
differ from that of the above in the fact that there seems to be an 
occasional variation in the formation of the internal basidia, being 
arranged in the form of a tetrad. It was first thought that such a 
condition was due to accidental displacement or something of the 
sort, but after a careful study of many stained and free mounted 
preparations it seemed that there was undoubtedly a tetrad formation 
of the promycelium. The appearance was noted alongside of the 
usual four-celled superimposed condition, and in the numerous 
preparations I have made, the tetrad appearance occurred most 
frequently at the inner edge of the sori in the angle formed by the 
branching of the mid-rib. In the hanging drop cultures where 
displacement or crowding would be impossible, the tetrad was 
observed and it germinated in the usual way, each cell sending out 
a single germ tube on the end of which is produced a sporidium 
and a promycelial nucleus passes out into each sporidium. Mounts 
from the germinating material from the cultures on the filter paper, 
made by removing with a needle a sorus with a bit of the epidermis 
and placed on a slide without cover glass, showed in one instance 
not only the typical promycelium but the tetrad in various stages 
of germination also. The two terminal cells had just begun to 
send out tubes, the nuclei becoming elongated and pointing toward 
the opening of the tubes. In another instance only one of the two 
lower cells had germinated. In one hanging drop culture a perfect 
tetrad with all four cells in a germinating condition fnrnished the 
most striking instance. At first the sporidium is uninucleate but 
its nucleus divides and since no cell-wall is formed, we have a 
binucleated sporidium. 
