38 British Uredinecs a7id Ustilaginece. 



to form elevated ridges. As an accidental variety, one 

 sometimes sees a few bicellular spores in the true Uro- 



myces spore-bed ; this has been ob- 

 served with Uromyces trifolii on Vicia 

 sepium. 



The teleutospores of Puccinia are 

 compound. They consist of two dis- 

 tinct spores borne on one pedicel. The 

 dilated upper extremity of the hypha, 

 which is destined to become a Puccinia 

 spore, soon assumes a fusiform shape, 

 and is uniformly filled with granular 

 protoplasm, while the lower part of the 

 hypha contains only a hyaline or watery 

 material (Plate III. Fig. 18). Soon a 

 delicate transverse septum appears near 

 Fig. 2.— Teieutospore thc middle of thc swollen part, dividing 



of iTrojnyces faba; germi- . , . , , 



nating, showing the germ- it trausvcrscly into two nearly equal 



canal through which the 



promyceiium has been pro- compartmcnts. Tlic sporc now becomes 



truded, and the develop- •■■ '- 



sTc:^4s1rom\b"or'down'! invcstcd by a stoutcr membrane (Fig. 

 wards. (Tuiasne.) ^ ^^^ ^^j^j^j^ gradually incrcascs in thick- 



ness so that the body now can be seen to consist of two 

 distinct accumulations of protoplasm. As the thickening 

 of the outer membrane goes on it becomes darker. This 

 thickening is most marked at the apex of the upper com- 

 partment. The granular protoplasm at first usually shows 

 two or three vacuoles (Fig. 20), but these become reduced 

 in number, so that in the mature spore only one is observ- 

 able (Fig. 21). How this vacuole is formed is not alto- 

 gether clear, but it probably is produced by the protoplasm 

 of each compartment accumulating more towards the walls 

 of the cell than elsewhere. Each compartment, then, con- 

 sists of a thick outer membrane, lined by a thin one (thc 

 endospore) which encloses the protoplasm and its vacuole. 



