Periodical Literature. 91 



BOTANY AND ZOOLOGY. 



Dr. Engler of the Swiss Experiment Sta- 

 New Light tion reports in an unusually well illustrated 



071 the number of the Mitteilungen the results of 



Influence 12 years' important observations on the 



of influence of light on the phaenology of 



Light. beech and other broadleaf trees as maple, 



ash, oak, and especially on the time of leaf- 

 ing, which has a considerable silvicultural bearing. He finds that 

 young specimens of these species open their buds earlier and are 

 earlier fully foliaged when standing under the shade of old 

 stands than when in the open or than older trees. Next follow 

 the lower twigs and branches of old trees, and then the tops of 

 crowns, and last the young unshaded plants. 



The difference in the beginning of budding between shaded 

 and unshaded young growth was 11 days and in the finish of 

 complete foliage 15 days. Neither temperature nor relative hu- 

 midity was found to produce this difference. The earlier leafing 

 out on north slopes than on south slopes by about a week sug- 

 gested the light as the operative influence, and a series of beech 

 partly grown under the influence of light, and others under shade 

 were subjected to observation. It was found that beech forms 

 buds in the shade or diffused light which open earlier and develop 

 foliage faster, than those formed on shoots exposed to direct or 

 stronger light. And this characteristic belonging to shoots and 

 buds formed under given light conditions persists for a number 

 of years after the light conditions have changed, and it takes 

 some time for them to adjust themselves. 



"Light" beeches also show superior form and growth when 

 planted in the open, than "shade" beeches, but when placed under 

 shade do less well than the latter. 



They also differ in habitus ; the light beeches show a plentiful 

 obliquely set foliage on upreaching shoots, while the shade beeches 

 have a horizontal spread of branch and foliage. The structure 

 of leaves also differs. 



The persistency of the acquired habit continues about as long 

 as the influence lasted beyond the time of the change of position. 

 While, however, intense light produces buds which bud late, on 



