264 
J. Ramsbottom, 
It is probable from this study that the homology of the spores in Endo¬ 
phyllum will be considered to be with the aecidiospores in the other 
genera as suggested by de Bary and not with teleutospores as Dietel 
* holds, although the additional fact of the fusion of nuclei in the ripe 
spore lends some support to Dietel’s view. 
An interesting case where apparently there is not a binucleate 
sporophytic stage has been studied by Moreau (1911). The observation 
was made on an Aecidium parasitic on Euphorbia silvatica. The aecidia 
have the usual appearance but when cytologically examined it is seen 
that all the cells are uninucleate. The elongated cells which support the 
chains of aecidiospores are uninucleate as are also those of the subaecidial 
mycelium. At no period is there a doubling of nuclei. In each of the 
cells at the base of the aecidium the single nucleus divides. A wall 
forms between the two daughter nuclei separating off at the summit 
a uninucleate aecidiospore-mother-cell. The second nucleus remains in 
the basal cell and contributes by the same procedure to the for¬ 
mation of a second mother cell and so on. The nucleus of each 
mother cell divides in its turn into two and a wall forms which 
separates the mother cell into two uninucleate cells, the upper 
larger one of which is a young aecidiospore, the lower smaller one an 
intercalary cell. Thus chains are formed. The aecidiospores grow, ripen 
and detach themselves, while the intercalary cells disappear. Thus every¬ 
thing occurs as ordinarily except that the cells are uninucleate and not 
binucleate. Moreau was unable to germinate the aecidiospores and there¬ 
fore could not determine whether she was working with Endophyllum or 
not. Plowright (Brit. Ured., p. 229) however, speaking of E. Euphorbiae 
says. — “The spores of this species germinate freely in water”. If the 
fungus is a species of Endophyllum we have a further type to add to the 
three referred to above. Whatever the genus, the point of interest is that 
this is the first record of parthenogenetically formed aecidiospores. 
Sharp (1911) has published a preliminary note on Puccinia Podophylli. 
A binucleate condition prevails in the mycelium that gives rise to aecidia and 
spermagonia. The nuclei even before there is any indication of aecidium for¬ 
mation are associated in pairs and divide conjugately. This condition is not 
however constant as a uninucleate mycelium is sometimes observed. The young 
aecidium arises in a dense tangle of hyphae beneath the epidermis of the 
host. Certain cells in this tangle enlarge and become “basal cells” giving 
rise to aecidiospore chains of the usual type but containing two, three or 
four nuclei according to the number of nuclei present in the basal cell. 
In older, chains only two of these basal cell nuclei continue to function 
so that binucleate spores usually far outnumber the others. It is not 
known how the basal cells arise. Spermatia formation has also been studied. 
Two facts recorded by the author with regard to these are very interesting 
in connection with the generally accepted view that the spermatia are 
male cells viz: 1. the spermatia are sometimes binucleate; 2. “the sper¬ 
matia vary in length, some of them being more than three times as long 
as the diameter of the nucleus, so that they contain much besides nuclear 
material”. When the author’s complete account of these phenomena is 
published it will be possible to decide whether in P. Podophylli we have 
the opposite phenomenon from the one described by Moreau i. e. a 
binucleate condition throughout the life history instead of a uninucleate 
