318 BROOKLYN BOTANIC GARDEN MEMOIRS 



behavior. During the previous two years he had secured scant 

 supplies of good seeds from a large pistillate tree fronting the old 

 Jones Home at 65th and Callowhill Sts. Throughout the summer of 

 1898 he examined it from time to time, and noted that the seeds ma- 

 tured wholly on the southeast side, though no staminate tree was 

 then known to exist for miles around. In the succeeding spring the 

 two staminate trees matured between 9 and 10 A.M. on May 5, and 

 by the 6th were equally free of pollen as before. But the possible 

 synchronous relation of these to the pistillate tree was now determined. 

 For, accompanied by one of his students and laden with staminate 

 branches, a visit to the latter tree was made on the 5th. A ladder 

 was secured and examination of the small green ovules on the branches 

 clearly revealed that each was exuding a shining viscous droplet for 

 pollen entanglement. The staminate branches were hung over the 

 western side of the tree and then shaken. As summer advanced the 

 abundant maturing ovules alike supplied wealth of material for study, 

 and by their structure showed that perfect pollination had been 

 effected. Continued study of the above trees in succeeding years 

 showed that synchronous maturation and rapid pollen discharge 

 annually took place as early as April 20 in 1913 and as late as May 22 

 in 1904, according to the stimulating amount of heat units, of rain 

 condition and of soil moisture. In time also as the above statistics 

 became known, the writer learned of staminate trees on the grounds of 

 Girard College, and Laurel Hill Cemetery, which doubtless had con- 

 tributed pollen to the pistillate tree, widely removed from them, during 

 previous years. 



The peach {Prunus persica) deserves attention as being an intro- 

 duced woody plant, that bears attractive flowers and valuable eco- 

 nomic fruit. Trees under like environment open averagely on April 

 22 and then in considerable numbers. Climax of blooming is reached 

 five days thereafter and within another four days the flowers have all 

 fallen. But in 1913 a sudden wealth of bloom appeared on April i. 

 It need scarcely be added here that a synchronous activity amongst 

 pollinating bees was a feature of the event. 



The common field daisy, that like the dandelion and English daisy, 

 are all European and introduced weeds, differs markedly nevertheless 

 from the other two in that it shows no unseasonable flowers through- 

 out the winter months and does not even unfold as a harbinger of 

 spring. For averagely a sudden wealth of flower heads expands on 

 May 24, and for a month thereafter added heads appear in what may 

 be— did we only know accurately enough — regulated succession. 



Almost exactly a month after the last, the first flowers of the intro- 

 duced moth mullen {Verbascum blattaria) come into bloom on June 



