8 Varietäten, Descendenz, Hybriden. — Eumycetes. 



the internodes between them are so short, due to the constricted 

 development that normal metabolism does not occur. Thus there 

 is a loss of one or two leaves, which on several acres of tobacco 

 may raake the difference between profit and loss. Hence, the grower 

 should not delay setting his plants in the field until they have 

 become over grown in the seed bed. Jongmans. 



Freeman, G, F., Physiological correlations and climatic 

 reactions in Alfalfa breeding. (American Naturalist. XL VIII. 

 p. 356—368. 1914.) 



The writer emphasizes the following final conclusion: 



In economic plant breeding one frequently encounters physio- 

 logically negative correlations such as those, in alfalfa, between 

 height and stooling capacity, height and percentage of leaves, and 

 between yield and quality. In seeking improvement, therefore, the 

 breeder must recognize and make use of these facts in the inter- 

 pretation of results obtained, and also search for races which violate 

 such naturaily antagonistic correlations to the greatest possible 

 exten t. 



At the end of the paper the author publishes the following 

 general conclusions. 



That the complex of allelomorphs, which we call a variety, may 

 be definite as both to ultimate composition and Organization is not 

 here questioned. When, however, we consider that visible charac- 

 ters are only the expression of the reactions of the vital forces of 

 the plant with the environment, we can realize that the variety, as 

 we see it, is not a definite thing, but is a result of two indepen- 

 dent classes of factors. Change either and the result correspon- 

 dingly changes. 



We are therefore to look upon a variety as a delicately orga- 

 nized chemical Compound. The various factors of climate and soil 

 may be compared to different physical influences to which the 

 original Compound may be subjected. The plant will react in agree- 

 ment with the different environmental combinations. Cultural and 

 climatic reactions often lead to error among those who assume them 

 to be mutative changes induced by the new conditions. That these 

 reactions may bring to light subraces with hereditary tendencies 

 not hitherto called into expression and which, by selection, may 

 be secured as pure races, is the probable explanation of many 

 cases of supposed direct climatic adaptation. 



Thus, realizing the true nature of a variety, we can draw fur- 

 ther upon the analogy of the chemist who investigates an unknown 

 substance by testing its reactions with a large number of known 

 reagents. In'like manner the breeder can only understand the true 

 nature of the hereditary vital forces within a plant after he has 

 tested and calibrated its reactions against a variety of soil and cli- 

 matic factors. These reactions are of fundamental importance to the 

 breeder and Student of heredity because they enable him to das- 

 sify, coordinate and Interpret the experimental results that he obtains. 



Jongmans. 



Engelke, C, Die Thelephoreen der hannoverschen Flora. 



(Jahrber. nath. Ges. Hannover. LX u. LXI. Bot. Abt. p. 99-110. 1912.) 



88 Arten werden aus dem Gebiete der hannoverschen Flora 



angegeben. Thelephoreen speciell Corticieen zu bestimmen ist eine 



