206 



HAPDWICKE'S SCIENCE- GOSSIP. 



decayed leaves. This observation was confirmed by 

 Mr. Vize, who wrote on May 22 : " According to 

 my examination, the Peronospora grows on the drier 

 parts of the magma. I do not observe it growing 

 on the very wet." 



Fig. 115. Resting- spores of Potato Fungus before and after Germination (see text) 



On fig. 115 may be seen a collection of resting- 

 spcres before and in the act of germination, toge- 

 ther with a nnmber of Peronospora threads taken 

 from potato-leaves and tubers previously infected 



with the oospores. A, B, c, and d show oospores in 

 which the protoplasm which is destined to produce 

 the new plant is coiled up within. At e this coil is 

 seen just emerging. This convolute mass is really 

 contained within a thin bladder, and sometimes 



the bladder is expelled, as 

 in Cvstopus, from the oogo- 

 nium before the coil un- 

 winds, as at f, g. The 

 thread then emerges as 

 shown at H, I, and j, some- 

 times leaving the bladder 

 free but broken, as at k, l. 

 It is rare to see the thread 

 of the new plant in con- 

 nection with the oogo- 

 nium, as at m, n, though 

 I have so seen it, together 

 with the septa many times. 

 The first mycelium or 

 spawn of the new plant 

 is seen at o, o, o, and 

 from this the Peronospora 

 springs direct, and (when 

 artificially grown) almost 

 invariably in a terminal 

 manner. The conidia are 

 not mature in any of the 

 specimens here figured ; 

 doubtless this is because 

 all the plants are more or 

 less abnormal from being 

 grown artificially ; but still 

 the threads are charac- 

 teristic of Peronospora in- 

 festans, and no known 

 fungus but the one which 

 causes the Potato disease 

 has vesicular swellings such 

 as are shown at p. 



Mr. Charles B. Plowright 

 (.surgeon, of King's Lynn), 

 a gentleman who has long 

 studied fungi, has patiently 

 examined some of the living 

 material with which I have 

 been working this spring 

 and early summer, and he 

 writes me on May 19 to say: 

 "I find plenty of branch- 

 ing, nodose conidiophores, 

 especially among the drier 

 portions of the substance 

 sent. I also see living 

 conidia. I have seen many 

 conidiophores with convoluted bases, but in the 

 vast majority of cases long ere the conidia come 

 the oospore is gone ; I see the granular protoplasm 

 distinctly ascending the base of the conidiophore." 



