22 



1. 1 per cent of full sunlight or more is necessary for the 

 survival of the plants studied. 



2. 8-15 per cent intensity is necessary for flowering and 

 fruiting. 



3. To insure reasonably good growth and the completion 

 of the plant's life cycle the light intensity should be 20 per 

 of full summer sunlight. 



4. Shading to 50 per cent intensity during the summer may 

 cause no marked decrease in the rate of growth and may be 

 beneficial for some shade-loving plants. 



5. In the forest, lack of vegetation under a canopy may 

 be due to lack of soil moisture if it falls below the wilting 

 coefificient, and to lack of light if it gets below 1 per cent 

 intensity. 



6. The complete solar spectrum is more efficient for the 

 growth of plants than any portion of it. 



7. The plants studied grow more efficiently without the 

 red region of the spectrum, than without the blue region. 



8. It seems highly improbable that sufficient change in 

 light quality takes place in passing through a forest canopy 

 to influence plant growth to any appreciable extent. 



Arthur H. Graves 

 Secretary 



NEWS NOTES 



During the week of August 13th the Plant Science Seminar 

 held its sixth annual session at the Massachusetts College of 

 Pharmacy, Boston, Mass. The Chairman, Heber W. Young- 

 ken, in his address gave as the objects of the Seminar the 

 bringing together of pharmacognosists for social contact and 

 the exchange of ideas and methods, the acquisition of new 

 facts by field trips and laboratory demonstrations, and the 

 stimulation of research in connection with pharmacognosy 

 and plant chemistry. He also referred to the fact that at 

 the seminar herbarium specimens from different localities 

 were to be exchanged. 



Dr. John Merle Coulter, the "Dean of American Botanists" 

 died on December 24, 1929. He served in several universities, 

 becoming head of the department of botany at the University 



