BOTANY. 719 



experiments were conducted upon varieties of the following plants: 

 Triticum durum, T. vulgare, T. amyleum dicoccum; rye, barley (Hordeum 

 vulgare, E. distichum, H. tetrastichum), and Stipa capillata. The experi- 

 ments were conducted by cutting- under water the heads from the stalk 

 and placing them in test tubes of distilled water, the heads being sup- 

 ported by a wire so that the stalks did not reach the bottom of the test 

 tube. Vegetable oil was poured over the water to prevent its evapo- 

 ration. From some of the heads the beards were removed; others 

 remained intact. The experiments were continued 2 to 3 hours and 

 frequent weighings were made. The amount of evaporation was cal- 

 culated to the unit of weight of the head. 



Summing up his investigation, the author concludes that when the 

 beards are large at certain stages of development they evaporate the 

 greater amount of water given off by the head, and cutting off the beard 

 strikingly diminishes the transpiration. In experiments with Byelo- 

 turka wheat it was found that 63.3 per cent of the water transpired by 

 the head was from the beards, and in another variety 60.3 per cent of 

 the total water evaporated was transpired through the beards. In his 

 experiments Avith Stipa capillata 67 per cent of the total was given off 

 through the awns. 



The intensity of evaporation is a temporary phenomenon possessed 

 by Byeloturka and black bearded wheat at the period of flowering, 

 while in the case of Stipa it was most abundant at the time when the 

 seed was in the milk stage. The percentage of transpiration by the 

 beards of Byeloturka varies from 22 per cent during early stages to a 

 maximum of 63.3 per cent and falls to 16.6 per cent during the period 

 of ripening. 



In relation to light, humidity, and the other factors which influence 

 evaporation, the author finds that the beards are not particularly sensi- 

 tive compared with other parts of the ear. The variation in the amount 

 of evaporation the author thinks is probably due to changes in the 

 anatomical structure of the beards, and suggests this can only be 

 determined by a thorough study of their anatomy. 



The removal of the beards from a part of the spikelets lowered the 

 weight of grain as much as 9 per cent in one experiment, seeming to 

 indicate that the presence of the beards is favorable to the proper 

 filling of the grain. — p. fireman. 



On the vegetative period of plants, L. P. Nilssen (TidssTcr. Norske 

 Landbr., 5 {1898), No. 5, pp. 283-28 (J). —The writer discusses the ques- 

 tion of the length of the vegetative period of cultivated plants in the 

 far north, as compared with that in more southern regions. Without 

 giving much direct evidence or results of prolonged observations, he 

 maintains that the popular idea is erroneous that owing to the pro- 

 longed light during the summer months at the arctic circle plants 

 mature more rapidly there than farther south. While the average 

 growing- period for six-rowed barley is placed at about 95 days for 

 southern Norway, and for oats about 112 days, he finds that the period 



