y6 The Scottish Naturalist. 



diseases that have attacked and ravaged the silkworm larvae, so 

 largely reared in Europe for the sake of their silk, which forms an 

 important product in many districts of the continent. 



If we seek to pass under review diseases of cultivated plants of 

 which Fungi are the cause, they prove to be far too many for even 

 an enumeration here ; and fresh investigations are continually 

 adding to the number of diseases known to be caused by them. 

 Only a few of the most serious diseases so caused may be men- 

 tioned at present. Farm-crops in Scotland at times suffer 

 greviously. Potatoes seldom escape wholly from the ravages of the 

 potato-disease fungus (Phytophthora infestans), and they are also 

 liable to injury from other less conspicuous Fungi. Turnips, in the 

 East of Scotland, fall a prey to the finger-and-toe disease, caused by 

 Plas??iodiophora Brassiccz ; and the cereals suffer from the " Rusts " 

 {Puccima stra??iinis and allied species). Of the vegetables cultivated 

 in our gardens, few are free from liability to such diseases. 

 Turnips and cabbages snow the effects of the Plasmodiophora, and 

 they are also liable, along with the other cultivated crucifers, to 

 the attacks of moulds (Peronospora pai'asitica, Cysiopus Candidas, 

 &c), which cripple and distort, or even kill the plants. Onions, 

 carrots, parsnips, spinach, and peas, all suffer from the growth of 

 moulds in or on them, which frequently seriously diminish the 

 crops. Raspberry bushes have their peculiar parasites (Phrag- 

 midium Rubi-Idaei, &c). So too have currant bushes, (Microsphaera 

 Grossularice, Glceosporium Ribis, &c.) Rose bushes are rendered 

 most unsightly by mildew (Sphcerotheca pannosd) ; and allied Fungi 

 frequently prove very fatal to the hop-plant in England, and to the 

 vineyards of France, rendering constant vigilance necessary to save 

 these crops from total destruction. 



Trees suffer greviously at times from Fungi. The larger kinds 

 burrow in the trunks, inducing decay, and pushing out their fruit- 

 ing masses from the sides of the trees in the form of toadstools 

 and ' Polypori of various kinds. The diseased trunks when ex- 

 posed to gales are liable to snap across at the parts occupied by 

 the Fungi. The foliage is frequently attacked. Everyone must 

 have observed the orange-spotted leaves of willows, poplars and 

 birches, when overgrown with Lecythea, the young stage of 

 species of Melampsora. Conifers are at times stripped of their 

 leaves by the action of similar Fungi, known as " rusts " from their 

 colour, belonging to the large group of Uredineae. The destruc- 



