Generations , and General Cytology of the Uredineae . 329 
does not reach the air, it usually grows on continually (Blackman, 7), the 
protoplasm with the nucleus being found at the end of the tube (Fig. 7). 
Division of nucleus. This form is not a favourable object for the study 
of this process on account of the irregularity of the germination and the 
difficulty of cutting the necessary sections. The divisions in the promy- 
celium were studied fully in the form to be next described, but here it 
was merely observed that not two (as Sapin-Trouffy states), but numerous 
chromosomes were formed on division, and that there was a definite spindle 
with centrosomes. 
Sporidia- formation. The four cells of the promycelium contain only 
small nuclei with a very small amount of chromatin, The sterigmata 
produced may either be short, as in the typical condition seen in Fig. 8 a ; 
or elongated, with more of the appearance of germ-tubes (Fig. 8). The 
difference appears to depend upon the degree of moisture present (vide 
infra under Gymnosporangium ). The whole of the protoplasm does not 
pass into the sporidia, but a small quantity remains in the promycelial cell 
(Figs. 8 a and 9). The sporidium is a globular or pear-shaped structure 
with a wall of some slight thickness and irregular in outline (Fig. 8 a), 
a nucleus which sometimes shows no nucleolus, but a well-marked chromatin 
network (Fig. 10). 
The sporidia germinate very readily, sometimes while still attached to 
the sterigma (Fig. 9), and often form a secondary sporidium which seems 
always to be binucleate (Fig. 11), and in one case four nuclei were 
apparently to be observed (Fig. 13). This binucleate condition is also 
sometimes to be observed in the primary sporidium even while it is still 
attached to the sterigma (Fig. 12). The condition with two nuclei appears 
to be fairly common in the primary or secondary sporidia of the group. 
It has been described in Puccinia Malvacearum by Sapin-Trouffy (48), in 
Endophyllum Sempervivi by Maire (29), and for Coleosporium Euphrasiae 
by Poirault and Raciborski (43), and it is to be sometimes found in 
G. clavariaeforme. It appears to be entirely without significance and to 
be merely a precocious division of the nucleus in which the usual wall- 
formation is delayed. The nuclei are certainly not paired (conjugate), for 
in Phragmidium and the first two species mentioned above the sporidia have 
been observed to give rise to a mycelium with single nuclei as in all other 
known cases ; in fact in E. Sempervivi Maire states that the two nuclei 
can be observed to pass into the infecting germ-tube and there become 
separated by a septum. 
Gymnosporangium clavariaeforme. 
M attire Teleutospore. The two-celled teleutospores of this form, with 
their very long gelatinous stalks by means of which the spores are held 
together in compact yellow masses, are well known (Fig. 14). As noticed by 
