Queries and Ans'wers. 499 



my observations, so far as they have yet been extended, I answer affirm- 

 atively, that " all the individual plants of any one species of any genus, to 

 which species a certain species of fungus is peculiar, are soil equally eli- 

 gible, whatever be their condition of health, for the seeds of that fungus 

 to germinate in or upon, and for the plants arising from these seeds to 

 thrive in or upon, and be nourished by ; " for I have known the parasitic 

 fungi to thrive on plants in the full vigour of health equally well with 

 those on trees in a decayed state. The observations which I have made 

 on the iEcidium cancellatum have led me to differ in opinion from the 

 idea which is advanced in Vol. IX. p. 331. : as I have only found it on 

 leaves that expand from the buds which were formed in the previous year ; 

 and that, when the spring shoot is taken within three or four buds of its 

 base, the leaves of the second, or midsummer, shoot (as it is termed by 

 gardeners; that is, the shoot produced from the buds of the spring shoot) 

 are entirely free from fungi. If the seeds of fungi be sucked up by the 

 spongioles, why are not the leaves of the second shoot infected with it ? 

 These are facts which lead me to believe that, when the ^cidium has 

 grown to maturity, and sheds its seeds, they drop between the scales of 

 the buds which enclose the leaves in embryo ; and is it not probable that 

 their minuteness enables them to enter the pores of the leaves, and ger- 

 minate in them, before these are protruded from the bud and expanded ? 

 I would, therefore, suggest to those who are troubled with this formidable 

 parasite, to wash their trees with caustic lime-water, adding a little salt, as 

 soon as the leaves are fallen in the autumn, and when the trees are dry; 

 and to repeat the washing two or three times. If the lime be left to settle, 

 the lime-water will not discolour a wall. lam. Sir, yours, &c. — John 

 Jemiings. Skij^stone on Stour, Worcestershire, June 28. 1833. 



The explanations in p. 329. of the cut in the same page, which exhibits 

 the progressive stages of growth and the structure of the jEcidium can- 

 cellatum, are lessened in clearness by the alphabetic sequence of the letters 

 of reference to which the explanations are affixed : the course of the 

 iEcidium's growth will be learned by reading the explanations in this 

 order : — a, c, b, d,ff, e e. — J. D. 



Art. VI. Queries and Answers. 



The Effects of Terrestrial Radiation on the Processes of Vegetation. 

 (p. 287.) — Sir, Every one engaged in the cultivation of plants, whether 

 in the garden or in the fields, must feel interested in the remarks presented 

 by your correspondent, J. Murray, Esq., on " the effects of terrestrial 

 radiation on the processes of vegetation." Much of the success of both 

 the gardener and farmer depends on meteoric agency and atmospheric 

 influences; and, though both these cultivators may know by experience 

 which are the best sites or aspects for their gardens or fields, yet it is per- 

 fectly true they cannot always explain the cause of their preference ; or 

 give real reasons why one situation is-better than another, or why the level 

 bottom of a valley is less suitable for a garden or field than the sloping 

 side of a hill. If the man in search of scientific information turns to the 

 article Meteorology in any encyclopaedia, he will find that the lower tern- 

 perature of a valley is asci'ibed, by one, to an excess of radiation ; by 

 another, to the greater evaporation ; and, by a third, to an accumulation 

 of the coldest air, which has descended down the sloped brows of the high 

 ground, and settles on the lowest places. I shall not venture to give an 

 opinion respecting these different notions ; but, seeking information, shall, 

 with your leave, describe a certain locality, with the meteorological circum- 

 stances experienced upon it ; and ask the opinion of Mr. Murray, or of 



K K 2 



