Spermogonia and the so-called Spermatia. 11 
of resembling a flask with a bristly mouth, it comes to be 
a cup-shaped depression on the surface of the leaf, sur- 
rounded by a hedge of stiff bristles (Plate I. Fig. 4). The 
function of these bristly paraphyses appears to be that of 
preventing the exuded mass of spermatia and jelly from 
being bodily washed off the surface of the leaf by rain. 
This is the more necessary, because it is during wet weather, 
as we have seen, that the spermatia, from the imbibition of 
moisture by their investing jelly, are brought to the surface 
of the leaf at all. The paraphyses occur with all spermo- 
gonia except those of the Phragmidia. 
Whatever their functions may be, whether as a spore- 
form or as spermatia properly so called, it is obvious that, 
by being held together by a viscid substance, their chance 
of dissemination by currents of air, etc. is but small. To 
a certain extent their diffusion over a limited area might 
take place in very wet weather. Rdthay* has, however, 
shown that the spermatial mass contains a certain amount 
of some saccharine material mixed with it—a substance 
which has the power of reducing Fehling’s solution; and 
further, that, as a matter of fact, insects do visit spermo- 
gonia for the sake of this saccharine matter, and are thereby 
unwittingly the agents for the distribution of the spermatia. 
Of this latter point, he obtained actual demonstration in 
the following manner. He had standing upon his window- 
sill some plants of Euphorbia amygdaloides, upon which a 
large number of spermogonia of Exdophyllum euphorbie 
were in the act of exuding their contents. One day, as he 
approached the window in question, he noticed some flies, 
which were busy upon these leaves, fly away from the 
leaves and alight upon the window pane. Closer scrutiny 
showed that the flies had left their wet footmarks upon the 
* Rathay, ‘‘ Untersuchungen iiber die Spermogonien der Rostpilze.” Wien: 
1882, 
