12 The Plant World. 



sons might enable the breeder to judge of the possible value of 

 selection in the variety in question. If, within any variety, 

 germinal variation is manifested in only slight degrees then it 

 may become a matter of difficulty to determine if any progress 

 by selection is being made. Mere observation of the plants will 

 hardly avail us. They must be studied by the best statistical 

 methods and even then many systematic errors will be encoun- 

 tered. It is scarcely necessary to state that the field indicated 

 is practically a virgin one, as almost no exact scientific work 

 has been carried out. Johannsen has but indicated the way. 



Interesting points are involved as to the relation of biotypic 

 to Mendelian characters. Two biotypes distinguished from each 

 other meiely by a moderate difference in mean seed weight or 

 by a character equally slight, may Mendelize upon crossing but 

 the discernment of such a phenomenon would scarcely b^ possible. 

 But there must come a time in the history of the vaiisty or of 

 the race, when differentiation is great enough so that segregation 

 may be noticed. Does this difference arise at once, or by a 

 summation of biotypic variations? 

 Laboratory Experimental Plant Breeding, 

 Cornell University. 



AN INTERESTING MARASMIUS FAIRY RING. 

 By Howard S. Reed. 

 The accompanying illustration shows a distinct 'fairy ring" 

 formed by Marasmius caryophylleus (Schaeff.) Schroet. (M. 

 Oreades), observed by the writer in September. This fairy ring 

 was found in a small grove of hemlock {Tsuga Canadensis) on 

 the campus of the Virginia Polytechnic Institute. As shown 

 in the illustration, the ring was approximately centered aiound 

 one of the hemlock trees located in the densest part of the 

 grove. On the left of the tree, where the ground was several 

 inches lower, the ring was interrupted by several wide distances 

 in which no fungi appeared. Nevertheless the ring could be 

 quite distinctly traced around thf tree. 



This very definite arrangement of the fairy ring with refer- 

 ence to the tree suggests some interesting questions regarding the 

 probability of mutual action between the two. The surface of 



