328 EXPERIMENT STATION RECORD. [Vol. 11 



sess very stable root systems. A detailed study of roots begun in Washington 

 and Idaho in 1914 is to be reported in a monograph on root systems. 



The influence of snow on the proportion of different vegetation at the same 

 altitude in the Pyrenees, J. Bouget {Rev. G6n. Bot., 30 {1918), No. 358, pp. 

 805-320).- — It is stated that the distribution of vegetation among the high 

 mountains is strongly influenced by the relief of the surface and by the dura- 

 tion of snow. At a given altitude, vegetation may be xerophilous on exposed 

 portions and hygrophilous on the flat or depressed areas, with all intermediate 

 gradations according to exposure. The upper limits of forests are determined 

 directly by these influences. This fact is thought to preclude the possibility 

 of restoring pine forests above the level of 1,800 metei-s (1.1 miles) on the 

 north slope of the Pyrenees. 



Beciprocal transplants, F. E. Clements and 11. IVI. Hall {Carnegie Inst. 

 Woshington Year Book, 17 {1918), pp. 292, 293). — A new method has been de- 

 vised for transplanting related species and ecads to determine the effect of a 

 change of habitat in causing adaptation and variation and in producing new forms. 

 The essential feature is the reciprocal planting as illustrated, insuring an exact 

 reversal of conditions and permitting a clear-cut demonstration of the extent to 

 which the varieties are reversible as well as plastic. For the sake of detailed 

 correlation, determinations of water content, light intensity, and air and soil 

 temperatures are made at occasional intervals after the plants are fully estab- 

 lished. Type specimens have also been preserved for comparison, and histologi- 

 cal material has been obtained for studies of leaf and stem adaptation. 



Synchronism in plant structures, J. M. Macfarlane {Brooklyn Bot. Gard. 

 Mem., 1 {1918), pp. 313-326). — A detailed account of pheuological and related 

 events observed during several years (a considerable period being considered 

 essential) states that for any one locality under like environmental conditions 

 the average annual period of seed germination, leaf formation, blooming, dis- 

 semination of pollen, and other responses by flowering plants seem to be syn- 

 chronous often to the day and even to certain hours of the day. In monoecious 

 and dioecious flowering plants, maturation of complemental floral organs seems 

 to be alTected in exactly synchronous relation, abundant pollination usually en- 

 suing. A like principle apparently applies to the maturation and dispersal of 

 spores and organs of conjugation. The behavior of plant hybrids suggests that 

 each is a blended combination of parental chai-acters as to period of living and 

 defoliation, blooming and pollination, capacity for climatic resistance, and 

 other phenomena, showing synchronous behavior, that is, a mean (all environ- 

 mental factors being considered) between those of its parents. 



A study in the anatomy of hazel wood with reference to conductivity of 

 water, M. G. Holmes {Ann. Bot. [London], 32 {1918), No. 128, pp. 553-567, figs. 

 10). — The author describes a statistical method of investigating the constitu- 

 tion of wood from the standpoint of its efficiency for conducting water. This is 

 an attempt to record deflnitely the number, size, and distribution of the elements 

 in wood which are concerned in this process and to present the results in a 

 graphical form. The method is designed to serve as a basis for correlating with 

 anatomy the facts of specific conductivity as obtained by experiments. 



In stool shoots of the hazel a very considerable variation has been observed 

 in the constitution of the wood formed during the first season. On the whole, 

 there is a general decline in total conductivity and a general rise in specific 

 conductivity from the base of the shoot to its apex. The explanation ofl'ered 

 is that these facts are related to the in-ovision for other functions carried out 

 by the wood and in particular to the greater proixji'lit^n of mechanical elements 

 in the lower part of the shoot supplying the necessary support in this region. 



