June 7,1924 Uninucleated Aecidiospores in Caeoma nitens 1055 
There is no structure known in the rusts which takes the place of or is the 
homologue of an egg apparatus. The factor which stands for such an organ was 
either discarded when the rusts were evolved, or it became recessive to the ex¬ 
tent that, for all that is known, the egg structure is always suppressed. It is this 
loss or impotency of the factor for that element of femaleness represented by 
the egg that distinguishes a rust most fundamentally from its ancestral alga. 
The existence of a strain of any rust characterized by the development of a 
2-celled -promycelium has not hitherto been reported. Inasmuch as the sup¬ 
pression of spermogonia has been said in this paper to be so constantly asso¬ 
ciated with the production of uninucleated spores with abbreviated promycelia % 
it might appear as though the writer looks upon the production of spermogonia. 
as inseparably connected with the faculty for initiating cell fusions. This may" 
indeed be true to a certain extent, but, as has been noted, the development of 
spermogonia does not always insure cell fusions, for a few cases of infection have 
been found where, though spermogonia were present, the spores were uninu¬ 
cleated. 
There is, of course, something in the inheritance of the rusts that determines 
when and where these cell fusions shall take place, as well as the nature of the 
cells fusing. The five great orders in the Florideae are distinguished mainly on 
the basis of the form and disposition of the carpogonial branches and auxiliary 
cells, and on the nature of the cell fusions which follow as secondary events^ 
The gonimoblasts or ooblastema filaments, sporophytic outgrowths from the 
fertilized egg, in many genera are also involved in these secondary fusions pre¬ 
liminary to the development of carpospores. It is to these secondary cell fusions 
in which the auxiliary cells of the red alga take the leading part that we must 
look for the homologues of the rust fusing cells. 
There being no organ such as an egg apparatus in the rusts, the spermogoma r 
though they are so well developed in many species, can not carry out their pri¬ 
mary male sexual function. Nevertheless, there may be a series of activities 
in the growth of the rust bound up (“linked”) with or influenced by the very 
inheritance which manifests itself morphologically in the shape of spermogonia. 
The fusions between the ooblastema filaments and auxiliary cells, and the other 
cell fusions in the red algae may very well be determined by the stimulus result¬ 
ing from the presence of some of that element of maleness normally derived 
from the spermatium during fertilization. In the absence of the sexual fusiona 
certain auxiliary cell fusions would not occur. 
Femaleness in the red algae outwardly expresses itself primarily in the organi¬ 
zation of the carpogonial branch bearing the egg cell and its trichogyne. Auxiliary 
cells are a secondary manifestation or accompanying phenomenon. In a dioecious- 
alga one should not expect to find auxiliary cells borne on the male plant. Female¬ 
ness in the orange-rust—that is, the power to develop an egg apparatus—has been 
lost. Auxiliary cells represented by the cells in the sorus primordium are the 
secondary expressions. These cells are capable of fusing, usually in pairs, undeir 
a certain stimulus. 
Maleness in the red algae is expressed in the form of antheridia (spermogonia^ 
producing spermatia. These bodies function primarily in fecundation, andjiiz 
certain groups, secondarily in the cell fusions subsequent to fertilization. In tile* 
rusts maleness has persisted as shown by the development of spermogonia with 
their spermatia, which are primarily functionless in the absence ofaneggappa*- 
ratus. This condition is associated with the occurrence of accessory cell fusions,, 
culminating in Gymnoconia in nuclear fusions in the teleutospore. 
‘ A long-cycled rust becomes short-cycled without losing the power to develop* 
that morphological structure, the promycelium. A promycelium may be formed! 
without there having taken place a nuclear fusion previously, in winch case- 
