Lecture on the Parasitic Fungi of the British Farm. 389 



the adhesive oily matter of the spores into that which is soapy, 

 which is easily washed off. This requires an alkali, and suggests 

 the use of a ley of potash, soda, or wood-ashes. Liming also 

 has a good effect. Sulphate of copper and arsenious acid, the 

 arsenic of the shops, are often used ; but, besides the other 

 objections to them,'there is the danger to the vegetative powers of 

 the seed. It is not usual to dress for smut^ which attacks not 

 only wheat, but barley and oats ; yet the same reason applies in 

 these cases, except that more difficulties are in the way because 

 of the dissipation of the sporules before harvest, and the remainder 

 being knocked out in threshing. It is important to ascertain with 

 certainty how the contents of the spores grow. Those of bunt are 

 too large to enter the stomata, yet if sown with wheat it reappears. 

 Some think the mycelium divides in the earth into molecules, each 

 of which has a vegetative power, and that any one absorbed by 

 the roots extends till it reaches its peculiar point of election in the 

 system. Others conceive that the spongioles of the roots imbibe 

 the fine contents of the spores, which grow. It is certain that due 

 dressings and washings prevent the reappearance of hunt, and 

 that excess of manure encourages red-robin and mildew, which 

 have also been observed to follow long feeding with sheep. 

 Amongst the antidotes to mildew, I venture to name clean farm- 

 ing, amendment of the texture of the soil, ventilation and letting in 

 light, checking over-luxuriance in the young plants, growing early 

 varieties in places subject to it, and avoiding putting on manure 

 directly before wheat, and hoeing the wheat when young. 



(7.) There seems no reason to believe that any uredo men- 

 tioned is deleterious, though hunt is disagreeable in the flour. 

 It has been said that in past times there were gingerbread-bakers 

 who had no objection to flour which contained the black matter 

 of bunt, as it saved them the brown sugar which they must other- 

 wise have used to render this confection sufficiently dark-coloured 

 for the approbation of their customers. If such customers there 

 ever were, they must have had more regard to appearance than to 

 quality. But I am now about to describe d. fungus closely allied 

 to uredo, which attacks grasses for hay, that appears to be quite 

 poisonous. It is termed ustilago, having a similar derivation 

 with uredo, and is left by Corda in his general classification, in 

 the same group. Tulasne wrote a long paper on ustilago in 1847, 

 with drawings. The one in question is called hypodytes. Its 

 spores are black, round, and very small, and I shall call \i grass- 

 smut. There was a great deal of it in 1848. In a field near 

 King's Cliffe almost every flower-stem of the hromus sylvatica, 

 which was one of the principal grasses, was infected by it. 

 A plan twas taken by Mr. Berkeley from this field, and instead 

 of its throwing up fertile spikes, almost every one is attacked, 



VOL. X. 2d 



