242 



Explanation of Plates. 



PLATE I. 



(All Figures X 250 unless otherwise stated.} 



PUCCINIA. 

 Fig. 



1. Portion of sheath of barley (Hordeum vulgare) showing numerous crowded black 



dots, the teleutosori of Puccinia sim-plex, the spring or orange rust of 

 barley ... ... ... ... ... ... ... nat. size 



2. Portion of sheath of wheat (Triticum vulgare}, the broad dark lines representing 



the uredosori of P. graminis, summer rust of wheat ... ... nat. size 



3. Portion of flag of wheat, the small dark dots representing the uredo and teleu- 



tosori of P. triticina, the spring or orange rust of wheat ... nat. size 



4. Uredospores of P. sim-plex from barley, the numerous germ pores appearing as 



paler dots scattered promiscuously over the face of the spore. 



5. Uredospores of P. graminis from wheat, with their three equatorial germ pores. 



6. Uredospores of P. triticina from wheat with germ pores promiscuously scattered 



over the face. 



7. Teleutospores of P. graminis from wheat, the thickened apex being very pro- 



nounced. 



8. Teleutospores of P. graminis from wheat, upper cells checked in their develop- 



ment by some unknown cause as shown by their pale colour, not due to ger- 

 mination having already occurred. 



9. Teleutospores of P. simplex from barley, only one being two-celled. 



10. Section of teleutosorus of P. triticina on wheat, with paraphyses at left. 



NOTE. The whole of the photomicrographs in this and the succeeding plates were 

 taken with the horizontal laboratory camera made by Messrs. Watson and Sons, of 

 London, using their Holoscopic lens of 12 mm. .65 N.A. to obtain the magnifica- 

 tion of 250 diams., and the 6 mm. .95 N.A. for 500 diams. 



