646 
Journal of Agricultural Research 
Vol. XXXI, No. ? 
to L). It would seem that there can be no question that the spores 
of Gallowaya are catenulate, since it is possible, in a sorus sufficiently 
developed, to trace the chain upward from the “two-legged” fusion 
cell below to the germinated spore above (fig. 1, I and L). Ordi¬ 
narily, then, one could say that at the middle of the mature sorus 
the chain of cells may be composed of a fusion basal cell; two to 
four short vacuolated binucleated cells; one or two elongated binu- 
cleated spores rich in cytoplasm; one or two long uninucleated spores; 
and the terminal germinated spore in the form of a four-celled in¬ 
ternal basidium (fig. 1, L). 
INTERCALARY ELEMENTS 
A feature which is brought out more or less diagrammatically in 
Figure 1, L, &, is well shown in Plate 2, D. In some of the chains 
of cells there is nothing to suggest that these intercalary structures 
are cells. At H, however, in Figure 1, d is a cell which is clearly 
degenerating, so that one might think thaf *both 6 and d are real 
intercalary cells. C. It. Orton has suggested to the writer that if 
such were the regular order of development throughout, it might be 
concluded that the sorus in Gallowaya is a modified aecidium. Such 
a form would round out an evolutionary series nicely. Until further 
evidence is found, however, the writer is compelled to consider this 
intercalary structure, 6, as formed merely by the elongation of the 
lower end of the lower cell of the basidium. The wall seems to become 
separated from the cytoplasmic contents above and elongates in the 
form of a stalk, pushing the basidium still farther outward. In an 
aecidium, for example, when the spore is formed, its sister cell is 
usually sacrificed to serve, as some hold, merely as a disjunctor, or, 
as others might claim, to make available sufficient food for the 
maturing of one of the pair. Where the upper daughter cell de¬ 
generates and the lower one becomes a spore, the first of these views 
could not be held. In some qases the intercalary cell elongates to 
perform the function of a stalk. In Gallowaya, some of the true 
spores fail to develop, and they may then elongate greatly and 
function as stalk elements. This intercalary portion seems to be 
simply the swollen end of the cell wall. 
Just how many of the cells in the chain function as spores is 
problematical. Typically, at any given time only the terminal ones 
do germinate. After the discharge of the sporidia the walls of the 
basidium collapse and disappear. Following this there is a sudden 
stretching or elongation at the lower end of the next spore. There 
appears to be a limit to the amount of elongation this spore can 
undergo before processes of disorganization begin. The next spore 
below, by elongating also, helps to bring the new terminal spore into 
a favorable position as regards its competitors (fig. 1,1). There is no 
question that as the sorus ages the lower spores in the chains never 
succeed in functioning as spores. They are, however, called upon to 
serve a very useful purpose, for it is only by their sacrifice in excessive 
elongation that the spore above can be brought into a position favor¬ 
able for the discharge of its sporidia (fig. 1. I to K). This sacrifice 
would not be necessary if young spores were being continuously cut 
off from the basal cell below. In an old sorus, therefore, one fre¬ 
quently finds germinated spores connected directly with the binu- 
