xxv.] CORN MILDEW AND BARBERRY BLIGHT. 183 



gathered from undiseased celery plants produced healthy 

 plants ; whereas seeds taken from celery plants diseased 

 with Puccinia Apii, Corda, produced seedlings every one 

 badly infested with the Puccinia. The plants were grown 

 in rows side by side in the same garden, and the clean 

 plants remained healthy all the season ; whereas the 

 diseased ones were destroyed by the hereditary disease 

 derived from the parent plants and presumably conveyed 

 from the parent to the offspring in the seeds. 



The Kev. M. J. Berkeley has published in the Gardener^ 

 Chronicle, 28th October 1848, p. 716, an instance of plants 

 of Pyracantha raised from seeds imported from Russia 

 being all killed by a species of Fusicladium ; whilst old 

 plants of Pyracantha growing at the same place remained 

 perfectly free from disease. The same gentleman records 

 an instance of a plant of Achillea Ptarmica, L., being given 

 to him by M. Desmazieres. When presented it was appar- 

 ently quite free from disease, but the donor knew that the 

 disease plasma of Labrella ptarmica, Desm., was in its 

 tissues. The Achillea was planted in March, and in the 

 following autumn the Labrella duly appeared, although 

 the fungus up to that time had not been seen in Britain. 

 It is common to find hollyhock seedlings showing the 

 Puccinia on their seed leaves. This we have traced to 

 the presence of pustules of the disease outside the seeds 

 or carpels, as illustrated by us in the Gardeners* Chronicle 

 for 1st July 1882, p. 23. Similar pustules occur on the 

 carpels or seeds of wild mallows. 



Many similar instances might be given ; they all prove 

 that Puccinia on mildew is hereditary, that it exists in a 

 finely-attenuated state in seeds taken from diseased plants, 

 and can be transmitted in a long interminable line from 

 generation to generation. No doubt it is possible that 

 living spores or mycelium may sometimes be present out- 

 side the seeds, but many fungi are able to reach the seeds, 

 as the fungus of bunt in corn, Tilletia Caries, Tul., and 

 Thecaphora within the carpels of convolvulus, etc. 



