14 



GERMINATION OF TELEUTosi'ultKs 



Ckhmixation of the Teleutospoee. 



We ii"\\ approach the consideratioD of a process which has 

 been in the past much discussed, and upon the right inter- 

 pretation of which the whole question of the systemal ic p« >>ition 



of the l/redinales depends. Kadi cell of tin- teleutospore of 

 P. Caricis has one germ-pore, though some genera allied to 

 Puccinia have toleutospores with more than one germ-pore to 

 each cell, e.g. Phragmidium, Uropyads, Calliospora. The germ- 

 pore of the upper cell is in the thickening at the summit, that 

 of the lower cell is lateral and just beneath the septum. Bach 

 of these pores is a canal passing through the cell-wall, and 

 covered only by the cuticle. Through these pores the germ-tube 

 passes, first appearing as a roundish swelling, the protoplasm 

 being surrounded by the thin endospore. This then elongates, 

 the nucleus squeezes through the relatively narrow pore and 



enters the tube where it divides 

 twice, and forms four superim- 

 posed cells, separated by thin 

 cell-walls (Fig. 16). This row of 

 four cells was formerly known as 

 a promycelium, but is now called 

 a basidium. If kept in water 

 these cells can round off and 

 separate from each other 1 , and 

 germinate by sending out a tube, 

 like the mycelial cells and spores 

 of many fungi. But if in a damp- 

 atmosphere, each cell without 

 separation produces a sterigma at 

 the end of which a basidiospore is formed, like the basidiospores 

 of Agaricini. These basidiospores can germinate at once, even 

 before they are detached from the sterigma, by sending out 

 a short tube which may produce a conidium resembling the 

 basidiospore at its end. 



Fig. 16. P. Caricis. a, a mature 

 teleutospore ; b, upper cell of 

 same, germinating and forming 

 a basidium ; c, basidiospores 

 germinating, x 600. 



1 This method is said to take place normally in Barclayella. 

 - It is noted by many observers that, in a state of nature, it is a layer of 

 dew, not of rain, that is favourable to germination. 



