170 1TNGOLD PESTS OF CULTIVATED PLANTS. 



with hoar-frost ; from the creeping mycelium arose the fertile threads, 

 which were rather sparse and flexuous, elongated, and septate (10-12 /u 

 diam.), branching irregularly. Conidia united in short chains, subglobose 

 or oval (14-15 x 12 /u), colourless. 



This has very much the appearance of an ordinary species of Oidium, 

 of which the vine mildew is a familiar type, and looks suspicious, as 

 though it were capable of doing mischief in a conservatory. 



Should it make its appearance we would advise spraying with diluted 

 Bordeaux mixture. 



Grevillea, xvi. 78 ; Sacc. Syll. x. 7081. 



Several other pests on Aroids have been described from time to time, 

 but they do not appear to have attacked any of the species cultivated in 

 Britain. 



EUCHABIS DISEASE. 

 Saccharomyces Glutinis (Cohn.), PL XV. fig. 27. 



This pest occurs on the leaves, petioles, and bulbs of Eucliaris 

 subdentata and upon Hymenocallis adnata, and caused some anxiety a 

 few years ago. The examination was undertaken by Mr. W. B. Grove in 

 1886, and he discovered that the cause of all the mischief was a very 

 .simple little fungus allied to the yeast fungus and the microbes. 



The cells of which the fungus is composed are round, oval, oblong, 

 elliptical, or shortly cylindrical (5-11 x 4 yu), either single or united 

 in twos, but seldom more together. The cell membrane and contents 

 -colourless when fresh, but when moistened again, after drying, with a 

 faintly reddish central nucleus. 



This is such a deeply seated endophyte that we doubt if the applica- 

 tion of fungicides would have any beneficial effect. 



Gard. Chron. Mar. 27, 1886, figs. 74-77 ; Grove, Syn. Pact. p. 63, 

 L 66 ; Grevillea, xiv. 132. 



ORCHID DISEASE. 

 Protomyces concomitans (Berk.). 



Previous to 1882, for many years, imported Orchids were known to be 

 liable to a kind of spot which baffled efforts to ascertain its cause. At 

 length Berkeley believed that he had solved the mystery through a species 

 of Dendrobium, the whole plant, and especially the leaves, of which were 

 much spotted. Abundant mycelium, connected with globose pale umber 

 bodies, immersed in the parenchyma was found, and to these was 

 attached the above name. In some places the mycelium was beaded or 

 moniliform. (Fig. 23.) 



The species of Protomyces are very simple in their structure, mostly 

 lying concealed in discoloured spots and of a destructive nature. It is 

 often that their presence is only suspected, mycelium alone being found, 

 until upon some fortunate occasion the sporelike bodies are met with. 



It need scarcely be said that in this instance the evidence is incom- 

 plete, as the details are too meagre to determine whether this is really a 



