262 proceedings: botanical society 



Whitney and H. S. Westover were unanimously elected to membership 

 in this society. 



The scientific program was as follows: 



Prof. A. S. Hitchcock reviewed (a) A paper by Trabut in which he 

 states that the oat commonly cultivated in temperate regions descended 

 from Avcna fatua, the Algerian oat from A. sterilis, and A. strigosa 

 from A. harhata; (b) a paper by Schulz on the origin of wheat, in which 

 he states that Triticum monococcum descended from T. aegilopoides, T. 

 dicoccum. from T. dicoccoides, and T. speJta from an as yet undiscovered 

 wild form; that the naked wheats are derived from the spelt wheats, 

 T. turgidwn, T. durum, and T. poloniciwi from T. dicoccum, and T. 

 vulgare and T. compactum from T. spelta. 



Dr. H. L. Shantz reviewed a paper by Sir Francis Darwin^ describ- 

 ing a method by which the influence of stomatal adjustment on the 

 rate of transpiration is eliminated. The stomata of the lower surface 

 of the leaf are locked with cocoa butter or petrolatum and incisions 

 made through the upper epidermis, thus connecting the intercellular 

 spaces with the outer air. By this method transpiration was found to 

 decrease proportionally as relative humidity increased. The straight 

 line relation led to the conclusion that a relative humidity of 105 would 

 be required to reduce transpiration to zero. 



Mr. C. S. Scofield, Chinese loild rice, with lantern (to be published 

 later) . 



Dr. p. Spalding, Present status of the white pine blister rust, with 

 lantern (to be published as a Bulletin of the Department of Agriculture). 



Mr. R. Zon, Meteorological observations for purposes of botanical 

 geography, agricidture, and forestry, with lantern. The inadequacy 

 of the present climatic data for the purposes of botanists lies not so 

 much in the kind and character of observations that are being recorded 

 as in the manner of their classification, their grouping, and computing. 

 To properly understand plant life it is essential to group meteoro- 

 logical data by actual periods of growth and rest. During each of these 

 two periods plants react to temperature of the air in an altogether 

 different way. The temperature records of the temperate region 

 of the United States should be computed separately on the basis of 

 the normal monthly mean not reduced to sea level for the period of 

 rest or the period of growth, and in some localities also for a third 

 period, the hot period. The period of rest should include all months 

 having a normal mean temperature of 48°F. or less. In the period 

 of growth should be included all months having a normal monthly 

 temperature of from 50° to 72°F. The hot period in temperate 

 latitudes should embrace months with a normal average temperature 

 of more than 72°F. 



A map showing localities with the same duration of the periods of 

 growth and rest has been tentatively prepared. 



1 Proceedings of the Royal Society, Series B, vol. 87, February, 1914. 



