ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 271 



terminal leader excepted) until late September and early October ; 

 phloem development as long as temperature permits. The total growth 

 of white pine extends over a period of five and a half months, growth 

 by cell-division between four and five months. Late wood formation 

 begins during the first half of August ; it is associated with a decrease 

 in growth intensity, and begins first in the higher parts of the tree. 

 Elongation of new shoots and leaves is simultaneous and begins in early 

 May ; it manifests itself only after xylem formation has begun. 

 Growth in length in the shoots ceases about July 1 ; needle-growth 

 may continue until August 15, or even later. 



White pine has long roots and short roots. Only the first elongate 

 to any extent, and often are in symbiosis with mycorhiza. Growth in 

 length begins during the last half of April, in some cases even earlier ; 

 no reliable data were obtained regarding its cessation. Secondary 

 growth occurs during the first season and proceeds in the usual way. 



General. 



Plant-Relationships.*— -W. Magnus reviews and criticizes a series of 

 papers by C. Mez and his pupils K. Golilke and L. Lange, dealing with 

 the relationships of plants, as determined by serum-reactions. The 

 first paper deals with the Angiosperms, the second with plants in general, 

 and the third with the Eanales. In his examination of the methods 

 and. results Magnus points out that while the conglutination tests are 

 suitable in some respects, they have many sources of error, especially in 

 the presence of variable amounts of albumin, such as are found in the 

 seed-extracts used. Moreover, the investigators' methods of obtaining- 

 concentrated solutions are faulty, and they have omitted to state the 

 percentages of the solutions. Previous investigations have shown that 

 it is unwise to assume that species are not related, even when certain 

 reactions fail, so that the results of the present papers must be accepted 

 with great reservation. Thus, the authors claim that the Cruciferai and 

 Papiveraceas are not related since they do not give the same reaction 

 with a particular serum, a conclusion which appears to be without 

 justification. The unreliability of serum-reactions is also shown by the 

 conclusion that the Cucurbitaceas and Saxifragaceas are closely related. 

 The results of such reactions should be regarded as general Dicotyledon 

 reactions. In several instances the results obtained by Lange with the 

 priizipitin-methods are contradicted by those obtained with the con- 

 glutination-methods, but it is probable that this is due to the action of 

 bacteria. This author seeks to prove that the Alismaceaa originate 

 from the Magnoliaceas because Alisma Phintago reacts with the serum 

 of the Magnoliaceae, but it is not shown that Butomus, which is more 

 typical, gives the same reaction. It is also claimed that there is no 

 connexion between the Berberidaceas and the Nymphseacese, but that 

 Podophyllum and Nijmphea are closely related. The reactions confirm 

 the relationship of the Leguminosas, Rosacea^ and Ranunculaceae. 

 Unfortunately the conclusions are frequently based upon reactions with 



* Zeitschr. Eot., lx. (1914) pp. 849-54. 



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