lo British Uredinecr and Ustila^inc{r. 



to the apex of the cone. The outer walls of this body are 

 embedded between the cells of the host-plant, and are like- 

 wise composed of similar fine hyphae, placed side by side. 

 A section of the spermogonium at this time shows its 

 interior to consist of similar converging parallel hyphae. 

 Very soon those hypha: which constitute the emerging 

 apex separate from one another, so as to appear as a brush 

 of stiff hair like bodies (paraphyses) ; in the centre of this 

 brush is a minute canal, which passes downward to the 

 interior of the body of the spermogonium (Plate I. Fig. 4). 

 The apices of those converging hyphae which occupy the 

 lower part of the spermogonial interior, are now seen to 

 be surmounted by very minute irregularly oval or rounded 

 bodies (Plate I. Fig. 5) — the so-called spermatia. These 

 spermatia vary in size, not only in the different species, but 

 also in the same spermogonium. In those I have examined, 

 they were from 5 to 8^ long, and 3 or 4 or even 6/i wide. 



Tulasne * gives the measurement of the spermatia of 

 Triphragmiiim iilmarice and Puccinia fj^sca as from 5 to 

 61X long, while those of most the yEcidia and of Cceonia 

 pingite and C. ribesii are rarely more than 4/i long. The 

 spermatia are produced in linear series from the apices of 

 the hyphae (sterigmata), which fill the interior of the sper- 

 mogonium. These are held together by a viscid, gelatinous 

 substance, which at first fills the bottom of the canal ; but 

 as more spermatia are produced, gradually the whole canal 

 becomes full, and eventually the mass oozes out at its upper 

 end in the form of a globule. The cause of the expulsion 

 of the spermogonial mass is, as De Bary f has shown, the 

 imbibition of moisture, which causes the investing gela- 

 tinous material to swell. As the spermogonium advances 

 in maturity, its flask-like neck opens out, so that, instead 



* Tulasne, "2" Memoire," p. 118. 

 t De Bary, " Brandpilze," p. 60. 



