66o 



UROMYCES ALOES COOKE. 



Stored food is exhausted by their own growth or the growth of 

 parasites. The nearest approach to typical sporidia formation is 

 shown in Fig. 6, g'^ and g'. 



Spermogonia. — Spermogonia have not been recorded 

 hitherto; but they appear to be plentiful, occurring on the leaves 

 with the teleutospore sori, but in groups distinct from the latter. 

 Occasionally a zone of leaf covered exclusively by spermogonia 

 merges into a zone on which only teleutospore sori are formed ; 

 sometimes a patch of the leaf bears spermogonia in the centre,, 

 surrounded by spore pustules 



The spermogonia occur in yellowish oval patches on the leaf, 

 which might easily be mistaken for the place of origin of teleuto- 

 spores. They differ from the latter, however in that the epider- 

 mis is firm and compact, never becoming abnormally raised ; the 

 spermogonia themselves are apparent as numerous orangc- 



FiG. 6. 



coloured specks, which turn dark brown on maturity. They are 

 of typical flask-shaped structure, opening to the exterior through 

 the stomata. {Fig. 5 a and b.) There are no ostiolar filaments. 

 Each spermatium {Fig. 5 r) is a minute oval cell (2 X 2.4 11), 

 with hyaline cell wall, and solitary nucleus occupying about Ys 

 diameter of the cell, with nuclear membrane and a few chromatin 

 granules. 



Inoculation. — In a number of artificial inoculation experi- 



