PESTS OF THE VINERY AND STOVE. 



327 



This may not be an injurious pest, as many of the species are sapro- 

 phytic, and the possibility would suggest itself, whether this mould has 

 not taken possession of a dead spot, caused by the Pestalozzia, and 

 become established upon it. At any rate, conidia of Pestalozzia were 

 sought diligently, and not a single one could be found. 



Grevillea, xvii. 42 ; Sacc. SylL x. 7837. 



Gardenia Canker. 

 PI. XIV. fig. 16. 



Tumours are formed on the stems, at the base, just above the ground, 

 or on branches near a fork, on Gardenia and also on Camellia. They 

 resemble other cankers, and appear to be the result of local irritation. 

 The bark around, which was at first, perhaps, a wound, swells, becomes 

 corky, and of a rusty brown, covering a patch an inch or more long. 

 When the centre of the tumour is bare, the woody tissue is seen to be 

 dead, and occupied by black dots, which are the thin receptacles of an 

 immersed Phoma, with minute narrowly elliptical conidia (7x2 /a). 

 This is not the cause of canker, but a sequence. Sometimes several scars 

 are confluent at the bottom of stems, and are swollen in a gouty manner 

 by the corky transmutation of the surrounding cell. 



Hoya Leaf- spot. 



Phyllosticta Bolleana (Sacc), PI. XIV. fig. 19. 



Forming spots on the living leaves of Hoya carnosa, which are 

 bleached to a greyish white, with an irregular brown margin, forming a 

 striking contrast to the bright green of the leaf. The receptacles are 

 scattered over the spot like minute black dots to the naked eye, containing 

 the small elliptical sporules, which are just tinged with grey (4-5 x 



It is doubtful whether the minute fungi of this genus, which forms 

 spots on living leaves, are to any considerable extent injurious to the 

 plant. They may become so by disfiguring the foliage, especially if they 

 spread themselves, but they are certainly incapable of inflicting such 

 injury as that caused by the various kinds of Anthracnose. Their life- 

 history is at present much involved in mystery. 



Probably, should any of them prove troublesome, it would be well to 

 submit the plants to treatment with one of the copper solutions. 



Sacc. Syll. hi. 70 ; Grevillea, xiv. 39. 



Another leaf-spot {Scptoria Hoyce) forms various white spots on Hoya- 

 leaves, girt by a brownish ring, sporules threadlike (20-25 x 1-H ^) or a 

 little club-shaped. In botanic gardens in Italy. 



Hoya Anthracnose. 

 Glceosporium affine (Sacc), PI. XIV. fig. 18. 



This spot has recently made its appearance in hot-houses at Glasgow, 

 and may soon travel southwards. It was previously known in Italy ; 



