82 INTRODUCTION TO THE STUDY OF FUNGI 



in that same garden, upon celery plants, during the succeeding 

 ten years. The inference certainly must be that the seeds 

 contained, in some occult manner, the germs of the disease, 

 transmitted in this way from generation to generation, and 

 not obtained by local infection of the seedling leaves, from 

 germinating promycelial spores. If the latter had occurred, 

 then the infection would not have been confined to plants 

 descending from infected parents, whilst other plants growing 

 within less than three feet did not show a spotted leaf; but 

 both series of plants would, on the contrary, have suffered in 

 an equal manner. 



Another case is related by Mr. Worthington Smith, 

 wherein he says it is common to find hollyhock seedlings show- 

 ing the Puecinia on their seed leaves. This he had traced to 

 the presence of pustules of the disease outside the seeds or 

 carpels, of which he gave a detailed account in the Gardener's 

 Chronicle. Yet another instance is upon record, in which a 

 well-known nurseryman had imported Dianthus seeds direct 

 from Japan. These seeds were carefully grown under glass, 

 and, immediately they were up in the seed-pans, they were all 

 attacked and destroyed by the characteristic Puecinia. On 

 making a microscopical examination of a series of these seeds 

 mycelium was detected inside the integument which surrounds 

 the embryo, or infant plant, and within the coat of the seed. 

 Another and equally conclusive incident has been narrated by 

 the Eev. M. J. Berkeley, in which plants of Pyracantha, raised 

 from seeds imported from Eussia, were all killed by a species 

 of Fusicladium, or black mould, whilst old plants of Pyracantha, 

 growing at the same place, remained perfectly free from disease. 

 In this last instance we have corroborative evidence, in which 

 the parasite was not a Uredine but a mould ; and the doctrine 

 of inheritance in plant disease is demonstrated to have taken 

 place with other parasitic Fungi, and is not confined exclusively 

 to Uredines. It is sometimes objected that these instances can- 

 not be referred to hereditary transmission, but that they are 

 simply cases of the transmission of a perennial mycelium. That 

 does not appear to alter the fact of transmission, for if the parent 

 transmits disease to its offspring, the disease is inherited from the 

 parent, whether it has been transmitted by germs or hyphae. 



