254 



and also to give him an idea of how much and what mineral constituents 

 he must apply from year to year to meet the demands of a thrifty tree. 



The writer is indebted to Prof. G. C. Caldwell, of Cornell University, for 

 the material and assistance that enabled him to carry on this investigation 



Poisonous effects of cyprepedium spectaiule. By D. T. McDougal. Pub- 

 lished in the Minnesota Botanical Studies, Part I ; 32-30. ' 



Symbiosis of isopyrum biternum. By D. T. McDoigal. Published in the 

 Minnesota Botanical Studies, Part II ; 139-142. 



The stomates of c ycas. By Ma.sox B. Thomas, 



Our present knowledge of the distribution of pteridophytes in Indiana. 

 By Lucien M. Underwood. 

 The purpose of this paper is not primarily to convey any new informa- 

 tion although it contains reference to some plants not hitherto reported 

 from this state ; nor for the purpose of criticizing what has hitherto 

 been accomplished though it notes the necessity of cutting out some of 

 the plants reported from the state that never belonged to its flora. Its 

 purpose is rather to indicate the paucity of information we have at hand 

 regarding the distribution of even the best known groups of plants ; to 

 indicate the extensive portions of the state that are practically untouched 

 by the hand of the collector ; to indicate how futile and useless it is to 

 publish or even make manuscript lists of the plants of any region and 

 leave nothing to represent this information aside from a mental recollec- 

 tion or a printed or written line ; to outline the limits of our definite in- 



