DR. J. H. GILBERT OX " FA.IR5T-RTNGS." 17 



Note on the Occurrence of" Fairy-Rings." 

 By J. H. Gilbert, Ph.D., F.B.S., F.C.S. 



[Read June 3, 1875.] 



It is known that " Fairy-Rings M occur chiefly, though not exclu- 

 sively, on poor pastures, and that they are discouraged by high (es- 

 pecially high nitrogenous) manuring. In the experiments on per- 

 manent meadow-land, conducted in Mr. Lawes's Park at Rotham- 

 sted, there are twenty different plots, representing nearly as many 

 different conditions of manuring, the same condition having been 

 continued on the same plot in most cases for twenty years in succes- 

 sion. Some of these plots yield an average of little more than 1 ton 

 of hay per acre, and others more than 3 tons. On some w fairy- 

 rings n occur, whilst on others they do not. The flora generally, 

 so to speak, has, indeed, changed under the influence of the dif- 

 ferent manures in a very striking degree. Thus, speaking 

 roughly, there are certain plots on which there develop annu- 

 ally from 40 to 50 species or more, whilst in others even less than 

 20 are in some seasons found. These differences, it should be 



m. 



remarked, are the result of the different conditions as to manu- 

 ring, the whole area, so far as could be judged, having been 

 pretty uniform in the character of the herbage at the com- 

 mencement of the experiments. 



It will be of interest, and be found not irrelevant to the special 

 subject of this communication, to summarize as briefly as possible 

 a few of the most characteristic changes which have taken place 

 in the botanical character of the vegetation under the influence of 

 certain characteristic conditions as to manuring. On three occa- 

 sions, at intervals of five years (namely, in 1862, 1867, and 1872), a 

 sample of the produce from each plot has been carefully taken 

 and submitted to careful botanical analysis. Taking the average 

 of the three separations, the following are some of the results : 



Continuously without manure (plots 3 and 12), the number of 

 species found in the produce has averaged 48, of which 17 are 

 grasses, 4 belong to the order of Leguminosae, and 27 to other 

 orders. The percentage by weight of grasses is about 62, that of 

 the leguminous herbage 8, and that of the remaining species, 

 which it will be convenient to term miscellaneous herbage, 30. 



With a purely mineral manure, containing superphosphate of 



LINN. JOURF. — BOTANY, VOL. XT. 



