PYCNOGHYTRIUM. Ill 



as zoospores swarming by means of a cilium. In addition, 

 resting-spores are developed singly or in groups. 



The first effect on the host-cell of the entrance of a swarm- 

 spore is that it becomes distinctly larger. At the same time 

 neighbouring cells are so stimulated that they multiply and 

 form a prominent ring-shaped swelling. The sporangia discharge 

 their zoospores on the host-plant itself, and these pass into 

 other cells of the swelling ; here they form resting-spores and 

 the host-cells die. Schroeter states that the resting-spores may 

 be found from August onwards. 



S. stellariae. Fuck. On Stellaria media and S. nemoruni. 

 The reddish-yellow hemispherical swellings are produced on leaves, 

 stems, flower-stalks, and sepals, either isolated or as a crust. 

 The resting-spores generally form brown crusts. The host-leaves 

 may be somewhat crumpled, but beyond this undergo little de- 

 formation.^ 



Chrysochytrium. 



(1) Forming simple vesicles: 



Synchytrium inyosotidis, Ktlhn (U. S. America). The epi- 

 dermal cells when attacked swell up to form club-shaped 

 processes, while the cells with no fungus remain unaltered. 

 The normal hairs of the host-plant are fewer on diseased than 

 on healthy parts. This parasite attacks Boragineae, e.g. Myosotis 

 stricta, IdtJwspermum arvense. 



S. cupulatum, Thomas, produces red eruptions on Potentilla 

 argentea and Dryas octopetala ; diseased cells of the host-plant 

 contain red sap. 



S. punctum, Sorokin. On Plantago lanceolata and P. media. 



S. laetum, Schroet. On Gagea. 



(2) Forming compound vesicles : 



S. aureum, Schroet. Attacks many herbaceous plants as well 

 as leaves of many shrubs and trees. Frequent on Lysimachia 

 Nummularia, Fragaria, etc. The cells attacked are swollen and 

 enclosed in a patch of enlarged neighbouring cells. 



S. pilificum, Thomas. On Potentilla Tormentilla. The 

 vesicles are hemispherical, and bear on their summits a tuft 

 of abnormally elongated hairs. Thomas^ found this species 



^ Clendenin {Botanical Gazette, 1894, p. 296) describes and figures a Synchytrmm 

 on Stellaria media in America (Edit.). 

 ^ Ber. d. dmtsch. hotan. Oen., 1888, p. 496. 



