BEY. M. J. BERKELEY — ON A PARASITIC FUNGUS. 



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about 120 were variegated, but (as I expected) in all sorts of 

 different ways. There is a part of my pleasure-ground where I 

 raised some score of the Pinus excelsa from seed ; some of these 

 are variegated, some conspicuously so. 1 have a deodar with white 

 leaves mixed with the green. I have had the common gooseberry 

 fol. var. I planted one or two score of acorns : one produced a 

 beautifully variegated oak. I have in a plantation one well- 

 grown fol. var. that I observed only a few years ago. I have a 

 common raspberry fol. var. A common holly sent out a shoot 

 fol. var. ; I made a layer of it, and, when it had taken root, sepa- 

 rated it, and made a beautiful plant of variegated holly. It is 

 now in the Kew Gardens. A field of lucerne always (at least 

 here) yields several, I should say many, plants fol. var. ; a field of 

 cabbages, several variegated, sometimes very beautiful ; so parsnips, 

 mangel-wurzel, and horse-radish. A variegated laurel is not un- 

 common ; but here they come sometimes (as one would call it) 

 spontaneously." 



V. On a Parasitic Fungus which causes Spot in Orchids. 

 By the Eev. M. J. Berkeley, M.A., E.L.S. 



Mr. Anderson has recently paid much attention to the spot in 

 Orchids, and has described four different kinds in the ' Gardeners' 

 Chronicle ' for February 18, 1865. Specimens of spot on ten 

 different Orchids, illustrating the different forms, were submitted 

 to me, by means of which I was enabled to confirm Mr. Ander- 

 son's observations in almost every minute particular. Amongst 

 these one was evidently produced by a parasitic fungus, and, as 

 might be expected from the deleterious action of many kinds of 

 mycelium on vegetable tissues with which it comes in contact, it is 

 one of the most destructive. It begins on the young leaves, causing a 

 brownish ill-defined spot ; after a time, this exhibits different shades 

 of olivaceous brown, and the parenchyma of the leaf becomes quite 

 pulpy and semiputrescent. On the underside of the leaf little raised 

 dots are seen which are caused by the cysts of a fungus beneath 

 them. The parenchym is more or less traversed by hyaline my- 

 celium with jointed threads, and each cyst or perithecium, which 

 is of a pale umber, is surrounded by a broad border of hyaline, per- 

 fectly colourless, jointed threads, the upper joints of which are 

 more or less swollen. In this condition I have seen no fruit. 



