Lafhorty and Pethybridge — Oh a Phytophthora Parasitic on Apples. 43 



Plate II. 



All figures reproduced from untouched negatives. Fig. 13 magnified 250 ; 

 fig. 14, 300 ; the remaining figures 720 diameters. 



Fig. 



1. Sexual organs of i'. Syringac from naturally rotted apple tissue. The 



antheridium is paragynous and the oospore not yet ripe. 



2. From the same source as 1. Tiie antheridium is amphigynons and the 



oospore is ripe. 



3. Sexual organs of P. Syringae from an apple pre\'iously inoculated with a single 



sporangium from a culture from the original rotted Irish apple. The 

 antheridium is paragynous and the oospore nearly ripe. 



4. Sexual organs of P. Syringae from the same source as in 3, but with 



amphigyuous antheridium. 



5. Sexual organs of P. Syringae from an apple rotted by product of germination 



of a single oospore derived from the original rotted apple. Antheridium 

 amphigyuous. Contents of oospore disorganized l)y clearing. 



6. Oogonium and amphigyuous antheridium of P. Syringae from single hypha 



culture from original rotted apple on raw apple cylinder. 



7. Sexual organs of P. Syringae with amphigyuous antheridium from pure 



culture on Quaker-oat agar originally isolated in Germany from Syringn 

 vulgaris. 



8. Sexual organs of P. Cactorum with amphigyuous antheridium on prune agar, 



from pure culture stated to have been isolated from Cactus seedlings. 



9. The same as 8, but fungus originally isolated from rotted apple in America 



(Whetzel). 



10. The same as 8 and 9, but fungus originally isolated from rotted apple in 



England (Bewley). 



11. The same as 8, 9, and 10, but fungus isolated from rotted pear from 



Switzerland (Osterwalder). Oogonial contents plasmolysed. 



12. Sexual organs of P. Fagi with amphigynous antheridium, from culture on 



cooked carrot, original isolation from Cactus seedlings (Peters). 



13. " Sphaero-conidia " of P. Cactorum isolated by Bewley from rotted apple in 



England. The lower one has a papilla over the empty portion of the hypha 

 on the left ; it also has a hyphal outgrowth above on which the upper 

 intercalary sphaero-conidiiim is borne. 



14. One unripe and two ripe papillate sporangia of P. Cactorum from rotted pear. 



Swellings similar to those seen in P. infestans are present on the 

 sporangiophore, where the two lower sporangia are borne. 



15. A single sporangium of P. Cactoriim from rotted pear, showing papilla and 



swelling of sporangiophore at point of attachment. 



16. A single sporangium of P. Syringae from Irish rotted apple, showing flattened 



apex and absence of papilla. 



