340 



SEXUAL KEPROBUCTTON OF PEEONOSPORA INFESTANS 



(lentnlly half washed out of its coating of cellulose by maceration in 

 water. At F the usual form of fructification is seen breaking through 

 a hair on the upper surface of the leaf, a very uncommon occurrence. 

 Another specimen is figured in fig. 5, where resting-spores have 



wc.5. ad.nat.del. 



Fig. 2. 



Peronospora infestans. — Oogonia and antheridia from badly-diseased leaves of 

 Potato after a week's maceration in water x 400. (Gard. Chron., p. 69.) 

 K. Eesting-spore with coat of cellulose. L. Eesting-spore washed out of 

 coat by maceration. M. Semi-mature resting-spores. N. Antheridia. 



Fig. 3. 



The -(4r^6/ro^7<sofMontagne and Berkeley X 400. (Gard. Chron., p. 69. From 



Journ. Hort. See, vol. i.) 



been formed in the stem of the Potato. Oogonia (FF) and anthe- 

 ridia (G) are seen in contact, as well as the resulting spore with its 

 cellulose wall (H) and separated mature resting-spores (JJ) in the 

 cells of the stem. At E arc some zoospores. From these figures it 



