ISO 



.'HARDWICKE'S SCIENCE-GOSSIP. 



ever, not only did many botanists at once differ from 

 my interpretation of the meaning of the bodies 

 found in diseased Potato plants, but the same 

 botanists differed from each other quite as much as 

 they differed from me. This fact, if it proved 

 nothing else, at least proved that the bodies under 

 discussion were new and unfamiliar. 



"My first published illustrations of the secondary 

 condition of the Potato fungus were printed in the 

 Gardeners' Chronicle for July 17, 3875, pp. 6S and 

 09, and (making allowance for the very slight and 

 insufficient material then at my command) these 

 figures may be taken in the main as fairly correct 

 representations of the early state of the resting- 

 spores. My illustrations bear a certain resemblance 

 to fig. 101, which represents a fungus named provision- 

 ally Pythium incertum by Mr. Renny. My plant 

 was, however (setting aside the anatomical differ- 

 ences), uniformly about one-third larger in all its 

 parts. 



Fig. 103. Condition of resting-spores from the isri potato- 

 leaves in April, 18/6. Enlarged 400 diameters. 



" Fig. 103 represents the condition of my Potato 

 resting-spores whilst still at rest, and before any 

 germination had taken place, drawn in the month of 

 -April last. 



Fig. 104. Pythium incertum, Renny. a, oogonium discharging 

 its undifferentiated protoplasm; b, oogonium discharging 

 its protoplasm in the form of zoospores ; c, zoospore free. 

 From the original materials. Enlarged 400 diameters. 



"Eig. 104 is Mr. Renny's Pythium Incertum. It 

 more or less agrees (as do all the other species of 

 Pythiiim here described) in its anatomical character, 

 with P. equiseti described and illustrated in the 

 Gardeners' Chronicle for May 27 last. Mr. Renny 

 some time since expressed an opinion that this 

 plant and mine were identical, but P. incertum is 

 smaller in all its parts, has non-septate instead of 

 septate (jointed) threads, and, as far as was seen. 

 P. incertum carried no male organs (antheridia). 

 Moreover, P. incertum produced no resting-spore, 

 but continually broke up into zoospores, and so 

 reproduced itself. It did not grow upon potatoes. 



" Eig. 105 is the famous Pythium equiseti of Dr. 

 Sadebeck, said to be found upon potatoes and 

 equisetum. This species was at first considered as 

 possibly identical with the bodies discovered by me, 

 and the original figure is here reproduced to show 

 the septate threads and other characters. The 

 upper figure, a, is remarkably like Artotroffus ; the 

 figures B, c, d have antheridia ' in local, but not in 

 anatomical relation with each other ' ; whilst at e 

 and F may be seen oogonia and antheridia ' free in 

 the surrounding space.' De Bary, in criticising a 

 similar figure of mine, says, 'These phenomena 

 entirely disagree with all that is yet known of 

 Peronosporete and Saproleguiecs' ; yet Dr. Sadebeck 

 and myself have seen and figured exactly identically 

 the same 'phenomena.' P. equiseti has been 

 proved to be different from my organisms. 



Fig. 105. Pythium equiseti, Sadebeck. From Dr. Sadebeck's 

 original illustration. Enlarged 400 diameters. 



" Pig. 106 is the new (?) Pythium vexans, found by De 

 Bary in collapsed potatoes. It is described by the 

 author as a new species, because it differs from all 

 similar organisms known to De Bary in its small 

 size and in the peculiar insertion of the oogonium 

 and antheridium. My readers will see at a glance 

 that this fungus is no smaller in any of its parts 

 than the two last described ; and as for the pecu- 

 liarity of the insertion of its oogonium and antheri- 

 dium, a, B, in De Bary's fig. 10G, do not differ from 

 r, g, ir, in Dr. Sadebeck's fig. 101. P. vexans (fig. 



