590 
Brooks .— The Development of 
A very large number of spermatia are produced within a spermogonium. 
They extrude from the orifice in a short coiled thread. The pycnidia of many 
other Pyrenomycetes (e. g. Valsa) and of certain members of the Sphaer- 
opsidales (e. g. Cytosporind) liberate their spores in the same way, but 
whereas the coiled thread in these cases is frequently as long as 7 mm., the 
thread in Gnomonia is less than a millimetre in length. When one of these 
threads of spermatia is put into a drop of water it becomes broken up into 
the innumerable spermatia of which it is composed. Doubtless in nature 
spermatia are scattered over the under surface of the affected area of the leaf 
by the action of rain or dew. 
Spermatia have been frequently seen adhering to the trichogynes whose 
structure will be described later (cf. Figs. 7, 8). It may be said here, how¬ 
ever, that the trichogynes pass out of the stomata in compact groups of two 
to five. In most cases observed, not one, but several, spermatia were found 
to be attached to one group of trichogynes. When one considers the enor¬ 
mous numbers of spermatia produced and the close proximity of the 
gelatinous trichogynes to the spermogenia, one recognizes that it is difficult 
for the trichogynes to escape having spermatia adhering to them. 
A large number of sections prepared during two successive years have 
been examined, but no definite evidence has been obtained for the passage 
of spermatial nuclei down the trichogynes. Occasionally what appear to be 
spermatial nuclei are seen embedded in the disorganizing matrix of the 
trichogynes and even at some considerable distance from their extremities. 
It is, however, a matter of great difficulty to be certain of the identity 
of such bodies at this stage because the degenerating nuclei of the tricho¬ 
gynes become elongated and, when stained, simulate the spermatial nuclei 
themselves. 
Attempts have been made to induce the spermatia to germinate, but 
without success. After prolonged immersion in water and various nutritive 
solutions they did not show the least indication of further development. 
Indirect evidence as to the lack of germinative power possessed by these 
spermatia is obtained from the circumstance that no newly infected areas 
appear on the leaves after spermogonial formation. Of course one must 
not lay too much stress upon the apparent inability of these spermatia 
to germinate, because it is well known that the spores of many parasitic 
fungi are often erratic in their germinative capacity. 
Upon considering the above data one is compelled, I think, to conclude 
that the spermatia of Gnomonia erythrostoma are abortive structures of the 
nature of male cells. Frank ( 17 ) came to the conclusion that they were 
male cells chiefly upon the ground that he had seen them attached to the 
trichogynes. The above account of their cytological characters and other 
facts cited in regard to them demonstrate more clearly what their nature is. 
V. H. Blackman ( 1 ) has shown that the spermatia of the Uredineae possess 
