*24 FUNGOID PESTS OF CULTIVATED PLANTS. 



reddish-brown line. Upon the upper surface of these rounded bleached 

 spots, but immersed in their substance, are numerous minute dotlike 

 brown receptacles, or perithecia, so small as to appear like pin-points to 

 the naked eye. 



The sporules, contained within these receptacles, are long and thread- 

 like, sometimes straight and sometimes flexuous, and colourless, escaping 

 when mature by a pore at the apex. 



It may be remarked here that the ordinary leaf-spots are produced 

 by fungi of three genera, all very much alike in external appearance, but 

 differing in the form of the sporules. In Phyllosticta they are very small, 

 about twice as long as broad, more or less, and undivided. In Ascochyta 

 the sporules may be similar, or larger, divided across the centre into two 

 cells. In Septoria the sporules are generally very long, and threadlike, 

 sometimes with a row of nuclei, or several transverse divisions. 



The above-named species is found in Britain, Belgium, and Italy. 



If troublesome, spraying may be useful to check it. 



Sacc. Syll. iii. 2811 ; Grevillea, x. 48. 



Septoria violicola is found on leaves of V. biflora in Switzerland and 

 Germany, and Septoria hyalina on two or three species of Viola in 

 North America. 



VIOLET ANTHKACNOSE. 

 Glcvosporiiim Violce (B. and Br.). 



Some years ago the Rev. M. J. Berkeley received some leaves of Viola 

 odorata from Scotland, with a parasite which he briefly described under 

 the above name. 



The leaves were disfigured by one or two pallid spots, which concealed 

 minute cavities scattered over the surface. In these cavities were 

 produced minute sporules, or conidia, which were expelled through 

 ruptures of the cuticle when moist, oozing out in little orange gelatinous 

 masses, and spreading themselves over the surface of the leaf. 



Thus far goes the description, and we have since seen the only 

 specimens which passed through Berkeley's hands, but fail to find any 

 trace of conidia or sporules on the discoloured spots ; and as the parasite 

 has never been found since, it must remain uncertain or doubtful. 



Grevillea, vi. 126 ; Sacc. Syll. iii. 3668. 



Another species of Anthracnose, which might possibly be the same, 

 has been found on Violet leaves in Italy, and called Marsonia Violce 

 (Pass.), the difference being that the spots are of a chestnut colour, and 

 the sporules, which are narrowly elliptical (15-18 x 5 yu), are divided 

 across the centre into two cells, the only distinction between Glceo- 

 sporium and Marsonia being that in the latter the sporules are bicellular. 



Sacc. Syll iii. 4036. 



VIOLET SMUT. 

 Urocystis Violce (Fischer), PI. I. fig. 19. 



In some gardens, for the past century, the Violet smut has been more 

 or less of a nuisance, disfiguring the foliage and weakening the plants. 



