356 ANNUAL EECORD OF SCIENCE AND INDUSTRY. 



consisting of the tree palmettos, palms, and yuccas of the 

 United States, embracing the Sabal palmetto from Florida, 

 one palm from California, two yuccas from Florida, and three 

 from Texas, Arizona, and California. 



The sections referred to are not mere hand specimens, such 

 as are usually found in collections, but in many cases they are 

 two or three feet long, and of the full trunk whenever this 

 is not too large for exhibition. 



LIVING TREES AT THE CENTENNIAL. 



Amongr the more interestino^ exhibitions at the Centennial 

 is a collection of living woody plants exhibited by Mr. Thomas 

 Meehan, of Germantown. These plants were all grown for a 

 certain time in boxes, with special reference to their trans- 

 plantation, and were inserted in the ground with balls of earth 

 around them, so that they are now growing very vigorously. 

 As this collection is for sale after the close of the Exhibition, 

 it oifers an excellent opportunity to any establishment in the 

 United States that wishes to secure a collection of American 

 plants of extraordinary completeness. D, III. Geioerhezei- 

 tuny, XXIII., 1876. 



CHANGES OF COLORATION IN FLOWERS BY ARTIFICIAL MEANS. 



The French Journal of Horticulture^ in an article upon the 

 changes of coloration which certain natural flowers undergo, 

 remarks that if violet flowers are exposed to the smoke from 

 a burning cigar they change color and assume a tint of green, 

 which is decided in proportion to the brilliancy of their orig- 

 inal color. This is due to the ammonia in the smoke. Start- 

 ino- out with this fact, Professor Gobba has made a series of 

 experiments for the purpose of determining the changes which 

 ammonia produces in the colors of difterent flowers. For this 

 purpose he merely makes use of a dish in which is poured 

 a small quantity of common aqua ammonia. Over this he 

 places a funnel, in the tube of which are inserted the flowers 

 to be experimented upon. In this way he has shown that 

 blue, violet, and purple flowers change to a beautiful green ; 

 deep red carmine flowers to black, white to yellow, etc. 

 These changes are most striking where the flowers have sev- 

 eral difl'erent tints, in which the red lines are turned green, 

 the white yellow, etc. An interesting example is that of the 



