436 



BOTANY OF THE LIVING PLANT 



which is really a septate basidium. The first step is the fusion of the 

 two nuclei to form one. Then follows its division into two and into 



Fig. 334. 



Longitudinal section through sorus of the teleutospores of Puccinia, on a stalk 



of Wheat-straw. Highly magnified. (After Marshall Ward.) 



four — in fact a tetrad- division, followed by partitioning of the four cells. 

 Each cell then forms a process, or sterigma, on the end of which a 



Fig. 335. 



m Two teleutospores of Puccinia germinating. In the one to the left each cell has 

 given ofi a promycelium, or basidium (a, a) ; to the right only the lower cell has 

 done so, and the promycelium has given rise to four sterigmata, bearing sporidia 

 (s, s) or baeidiospores as they are better called. Very highly magnified. (After 

 Marshall Ward.) 



