UREDINALES 



577 



the membrane of the spore stipe changes into a substance capable of 

 swelling in damp weather, leading, especially in Gymnosporangium, to a 

 gelatinization of the telium. The mature spores are capable of immediate 

 germination, and in Gymnosporangium are thin walled in the interior 

 of the sorus. 



In Gymnoconia, Triphragmium and Kuehneola, the teliospores have 

 developed in a special direction. In Gymnoconia (Fig. 389, 4 and 5) the 

 apical cell divides, as in Puccinia, into two superimposed daughter cells. 

 Their germ pores are much distended and their form very variable. In 

 Triphragmium (Fig. 390) they divide triangularly into three daughter 





Fig. 388. — Phragmidium violaceum. 1. Young teliospore with stalk. 2. Somewhat 

 older stage. 3. Section of mature teliospore showing germ pores. 4. Teliospore with 

 swollen base. 5. Puccinia Podophylli. Development of teliospore. (1, 2 X 700; 3 X 

 535; 4 X 300; 5, partly diagrammatic; after Blackman, 1904; Christman, 1907.) 



cells, the lowest sessile on the stipe. In Kuehneola (Fig. 389, 8) they cut 

 off successively, single unicellular teliospores which lie one above the other 

 in a chain, as the chambers of Phragmidium, except that they arise in 

 basipetal sequence instead of by repeated division into two, and are con- 

 sequently not surrounded by a common membrane of the mother cell. 

 The teliospores of Gymnoconia and Triphragmium are true resting spores, 

 those of Kuehneola are capable of immediate germination at maturity. 



The following genera are connected directly to Uromyces in the form 

 of their teliospores which do not arise in hypodermal telia but are associ- 

 ated in special spore masses raised above the host tissue. 



In one direction has developed Hemileia (Fig. 391, 2), whose telio- 

 spores, like the urediniospores which belong to it, are cut off at the tip 

 from a columnar fascicle of hyphaeand are bound together by a gelatinous 

 sheath into a spore head which falls apart by pressure. 



