358 EXPERIMENT STATION RECORD. 



The conifers of China, L. Beissnkr (Bui. Soc. Bot. Hal., 1898, \<>. 6, pp. 166-170). 



Tilia cordata, E. G. Baker (Jour. Hot. [London], 36 ( 1898 I, So. 428, pp.318, 319). 



An exact method for determining the season in -which timber has been felled, 

 P. I. Rasheyski ( Warsaw, lS97,pp. 17 : abs. in Selsk. him:, i Lyesov., Is: 1 1897), j>. 1 16). — 

 The author describes a method for determining by use of the microscope whether a 

 given piece of timber was felled in summer or winter. The method is illustrated by 

 drawings of microscopic sections of pine felled in different seasons. — p. fireman. 



SEEDS— WEEDS. 



Heat of imbibition by seeds, G. Macloskie (Bui. Torrey Bot. 



Club, 25 (1808). No. 5, pp. 272-271). — The author states that the expla- 

 nation of tbe production of heat in germinating seeds by destructive 

 metabolism is not sufficient to explain the rising of temperature or cer- 

 tain cases of germination which have occurred at very low tempera- 

 tures. He reviews briefly the various opinions relative to the physics 

 of imbibition, and describes a limited experiment in which dried peas 

 with water were placed in a bottle and beside it a control bottle con- 

 taining water, the initial temperature of the two being the same. In 

 about an hour the temperature of the first bottle had increased about 

 1° C. over the check and remained about this much higher for 3 days, 

 when the peas began to germinate. 



In the second experiment, conducted in a somewhat similar manner, 

 the author used dry split peas devoid of seed coat, without radicle or 

 plumule, so there could be no germination. They absorbed water 

 quickly and in a short time the temperature was 1° C. higher than that 

 of the control bottle. This continued for 15 hours, by which time the 

 seeds had become thoroughly saturated, when the temperature fell to 

 that of the water in the other bottle. The author states that a differ- 

 ence of 1° O. will certainly not appear insignificant since the tempera- 

 ture of germinating peas was only 1.5° 0. higher than the surrounding 

 air, as determined by experiments of Sachs. No attempt was made to 

 estimate quantitatively the amount of heat which was evolved. 



The author believes that in the experiments cited by Uloth in 1871, 

 in which seeds were found germinating in ice, while the initial heat 

 may have been due to some external cause, after the seeds had become 

 wet the heat produced by imbibition might have melted the ice to such 

 an extent as to account for the germination. 



The influence of X-rays on germination, Maldinev and Tuou- 

 venin (Rev. Gen. Bot, 10, No. Ill, pp. 81-86. ph. 2). — The authors 

 briefly review the somewhat limited literature on this subject and give 

 in some detail a series of interesting experiments in which the effect of 

 X-rays on the germination of a number of seed was investigated. The 

 seeds tested were millet, Convolvulus arvensis, and Lepidium sativum. 

 The form of apparatus used is figured and described. Check seeds 

 were protected from the action of the X-rays by means of leaden plates. 

 From the results of the experiments the authors conclude that X-rays 



