THE AMERICAN BOTANIST 89 



rocks. The rings were sometimes no larger in diameter than 

 a led pencil and ranged in size up to two inches across. But in 

 every case they were quite symmetrical, bright orange-brown 

 at the edge, and dull brown in the center where the older parts 

 had died. When young these lichens form a small circular 

 spot. Growth can of course take place in all directions and as 

 long as the rate is uniform on all sides the circular form will 

 he maintained. The older, central parts soon die off, and the 

 result is a small, but perfectly formed, fairy ring. 



A larger ring, but due to tlie combined influence of growth 

 and death in the same way, is exhibited by the moss-like Selag- 

 inella rupestris. The plant starts from a small circular mat 

 which lies flat on the ground and spreads uniformly in all di- 

 rections. Its center eventually dies away, leaving a bright 

 green ring of live plants which, contrasts strongly with the 

 black, deadened portion within and soil without. These rings 

 vary from one to three feet in diameter, and the living zone at 

 the circumference is two or three inches wide. There is no 

 apparent reason why they should not exceed three feet in size, 

 but no larger perfect rings have been seen Parts of the ring 

 may die, or obstacles may be encountered, and in this way the 

 ring is broken or its symmetry destroyed. One may easily find 

 arcs of circles, which if complete would be four or five feet 

 across. The most peculiar feature of these fairy rings is that 

 a second may appear within the first, or that two of them may 

 overlap. 



In Kerner's "Natural History of Plants," which, by the 

 way, is a regular storehouse of information and suggestion for 

 the out-of-door botanist, one may read of the rings formed by 

 certain kinds of European grasses. In this country a low 

 sedge, Carex umbcllata, and a common grass, Andropogon 

 scoparius, both produce very sharp and well marked rings. 

 They also are formed by radiating growth and the subsequent 

 death of the older, central parts. Both species produce large 



