FUSICLADIUM. 267 



The general appearance and occurrence of the disease in the 

 Colony has been dealt with by Mr. Lounsbury in the Cape Agricul- 

 tural Journal, No. 14, of 1905, so that without travelling over old 

 ground we shall confine ourselves to the miscroscopic investigation. 



For this investigation, a large supply of material, including 

 diseased leaves, twigs and fruits of both Apple and Pear collected 

 from various orchards in the Colony, was forwarded from time to 

 time by Messrs. Lounsbury and Dewar, Government Entomologists 

 at Cape Town and Grahamstown. In addition, while in the Colony 

 in March, material of diseased Pear was obtained at Worcester, 

 Paarl, Stellenbosch and Cape Town, and of diseased Apple at 

 Stellenbosch. 



All the material examined was found to be producing abundant 

 conidia from the disease spots. From the nature of these conidia and 

 their conidiophores, it was evident at once that we were dealing with 

 two distinct fungi. In spite of this fact, a sharp look-out was kept 

 to see if infected Apple material ever showed signs of being infected 

 with the fungus found on the Pear, or Pear material to be attacked 

 with the fungus fc>nnd on the Apple. No indication of this was 

 found in any of the examinations. 



By some authorities the fungus occurring on the Apple is con- 

 sidered to be identical with that on the Pear ; by others they are 

 regarded as two distinct species. 



To constitute a specific difference between two plants, we must 

 be able to point to some morphological character by which we can 

 distinguish the one from the other. A reference to the figures of 

 these two fungi will, I think, clear up any further doubt regarding 

 them. 



FUSICLADIUM DENDRITICUM, FCKL. 



In Figure I., Plate, p. 268, is shown a section through a small 

 disease spot of F . dendriticum on the Apple, of the variety known as 

 the " Late Bloomer." It will be seen that the mycelium bursts 

 through the epidermis, and a succession of spores is constricted off in 

 a continuous fashion. 



The ripe conidia (Figure II. a.) when sown in water soon 

 germinate (Figure II. b.). The spore always becomes septate, and 

 gives rise to the germ tube (Figure II. b. and c), which eventually 

 bears secondary spores. 



FUSICLADIUM PIRINUM, FCKL. 



In Figure III., Plate, p. 268, is shown a section through a dis- 

 ease spot on the Pear, of the "Saffraan" variety. For some little time 

 the mycelium remains covered by the epidermis, through which it 

 sends up here and there, stout conidiophores, which have a studded 



