Miscellaneous. 387 



was placed on end, with its lower part sunk about 25 centimetres 

 below the level of the soil, within a sort of tub large enough to leave 

 between the two an annular space open above and 6 or 7 centimetres 

 in width. The plastered bottom of this cask was bordered all round 

 to a height of 8 centimetres, so that a vacant space of the same 

 height was left beneath it. The cask was kept always full of water, 

 and completely exposed to the sun during the long summer days ; so 

 that the atmosphere contained in the vacant space beneath it must 

 have been at once hot, moist, and dark ; and the layer of plaster 

 itself was a soil placed under favourable conditions in some re- 

 spects. 



At the end of September 1809, the author found upon the lower 

 surface of this layer of plaster more than 500 individuals of a small 

 Agaric belonging to the genus Co_prinus. They were at various 

 stages of development, about half of them being already mature ; 

 these were from 3 to 4 centimetres in height, with a slender cylin- 

 drical stem and a moderately convex, delicate hood, varying in 

 diameter from 12 to 15 millims. Their colour was pale, slightly 

 tawny, but the hymenial lamellae were of a brownish violet tint. 

 The author believes the species to be Agaricus (CopriuHs) radians, 

 Desmaz. 



The entire group of Agarics occupied about a quarter of the 

 whole circular layer of plaster, the remaining three-quarters being 

 destitute of them. They were all towards the southern part. 

 Springing from the roof of the cavity under the cask, they had 

 grown from above downwards, or in a direction opposite to their 

 natural one ; but their stems departed from the vertical by at least 

 30°, their direction being towards the north. Upon this fact the 

 author remarks that it is in opposition to the hypothesis, particu- 

 larly maintained by Hofmeister and J. Sachs, that the action of 

 gravity has much to do with the direction of the organs of plants : 

 if the little Agarics had yielded to the action of gravity, they would 

 have followed the vertical line, from which they all departed. 



The author also calls attention to the difficulty of understanding 

 the cause of the deviation towards the north. The Fungi generally 

 bend towards the hght, like Phanerogamous plants ; and the au- 

 thor records an experiment made by him with Claviceps puyyiirea 

 growing on ergotized wheat, which constantly turned its stem at an 

 angle of about 45°, in order to direct its head towards the light ; so 

 that, when it had been moved two or three times, its siem had be- 

 come entirely sinuous. But this motion '^•ould not have iutluenced 

 the fungi no iced by the author, as no i-ght could penetrate the 

 space in which they grew ; and, moreover, they had directed them- 

 selves from the south or sunny side towards the obscurity of the 

 north. Their stems, also, were quite rectilinear. 



The most remarkable fact noticed by the author is the following. 

 From the exceptional position in which these fungi were developed, 

 their direction was, of course, reversed, and the hoods had their free 

 and naked surface, which is usually superior, t irned towards the 

 ground, whilst their hymenial surface, with its lamella?, was turned 



