THE RUSTS OF NOVA SCOTIA. FRASER. 321 



the western United States and Mexico. The amphispore is 

 evidently a uredospore which has developed the function of a 

 teliospore. 



Teliospores. 



These are the last spores of the life cycle. It may possibly 

 be that in some cases they are absent, but usually it is simply 

 a case of not having been found. Teliospores are very varied 

 in their forms and on this account have been used largely for 

 purposes of classification. More stress is now laid on other 

 characters. 



They arise like the urediniospores in sori called telia or 

 teleutoeori, beneath the cuticle or the epidermis. They usually 

 break through the epidermis at length, though they may remain 

 covered. The sori may be pulverulent or compact and often 

 dark in colour, though sometimes colourless or bright coloured. 

 They may be borne on. pedicels or sessile. In one genus 

 (Endophyllum) not represented in !N"orth America the telio- 

 spores originate in chains and are surrounded by a peridium 

 regarded as the test of the teliospore. The walls of the telio- 

 spores are usually much thickened and may be smooth or 

 verrucose, but never echinulate. Sometimes finger-like pro- 

 jections are present at the apex, as in Puccinia Loin. The 

 number of cells varies from one in Uromyces to several as in 

 Phragmidium. The number of germ pores in a cell is usually 

 one. In Uromyces it is always placed at the apex. In the 

 genus Phragmidium and Gymnosporangium there are several 

 in each cell. 



The telia as in P. "rubigo-vera" is often divided' into com- 

 partments by modified hyphae, which have been called para- 

 physes, but Arthur regards this as a stroma and not part of the 

 sorus ; he regards such sori as compound. 



Some teliospores germinate at maturity on the host plant. 

 But the teliospore is primarily a winter spore, whose purpose 

 is to tide the plant over winter, and the majority will not 



