GYMNOSPORANGIUM 



315 



chains. Closely allied to Phragmidium, differing mainly in 

 the relatively greater number of cells forming the teleuto- 

 spore. Both stages grow on the same host-plant. 



Burnet leaf spot (Xenodochus carbonarius^ Schlecht.) is 

 parasitic on this plant. The aecidium stage forms large, 

 orange-red, roundish patches on the leaves, and elongated 

 patches on the stems. This is followed by the black, wart- 

 like pustules of the teleutospore stage on the leaves. Only 

 met with in this country on Sanguisorba officinalis. 



Aecidiospores subglobose, yellow, warted, produced in 

 short chains, then becoming free, 15-25 X 14-20 /A. 



FIG. 94. Xenodochus carbonarius. i , teleutospore pustules 

 on Burnet saxifrage, nat. size ; 2, a single teleutospore, 

 highly mag. ; 3, a chain of uredospores, highly mag. 



Teleutospores cylindrical or worm-like, often curved, 

 composed of 10-20 globose cells, much constricted at the 

 septa, smooth or minutely warted towards the apex, dark 

 brown; individual cells 15-20 p diam. ; stalk short, hyaline. 



GYMNOSPORANGIUM (HEDW.) 



Teleutospores forming large subgelatinous masses, oozing 

 out from the bark of the matrix (always Junipers in this 



