proceedings: botanical society 313 



THE BOTANICAL SOCIETY OF WASHINGTON 



The 119th regular meeting of the Society was held in the Crystal 

 Dining Room of the Ebbitt Hotel, Wednesday evening, March 14, 

 1917. Seventy -four members and sixty-five guests were present. Mr. 

 T. H. Kearney, President of the Society, presided. Mr. A. S. Hitch- 

 cock, the retiring President, delivered an address on Taxonomic bot- 

 any and the Washington botanist. A full text of this address appears 

 elsewhere in this Journal. 1 



The 120th regular meeting of the Society was held in the Assembly 

 Hall of the Cosmos Club at 8.00 p.m., Tuesday, April 3, 1917; eighteen 

 members and one guest present. 



Under "Brief Notes" Dr. W. H. Evans showed a Lummiere plate 

 of a pineapple field in Hawaii, part of which had been sprayed with an 

 8 per cent solution of ferrous sulphate. The sprayed portion of the 

 field was a deep green color and produced an excellent crop while the 

 unsprayed portion was yellow or pale green and the crop practically 

 a failure. 



The regular program consisted of the following papers: 



The control of the white pine blister rust: Haven Metcalf. (Illus- 

 trated with lantern slides.) The white pine blister rust apparently 

 originated in Asia and spread into Europe upon Pinus cembra. When 

 the white pine (Pinus strobus) was introduced into Europe it proved 

 to be subject to the disease. The first record of importation of white 

 pine transplants from Europe to the United States dates back only 

 to 1899. The disease was first reported in America in 1906. Since 

 that date enormous quantities of diseased nursery stock have been 

 imported. The pathologists and foresters of New England and the 

 Middle Atlantic States discouraged importation of white pine seedlings 

 after June, 1909, and importations was made illegal in 1912. 



The disease has spread more rapidly and posessed greater virulence 

 in New England than it did in Europe. At first it was hoped the dis- 

 ease would prove to be only a disease of nursery stock but at several 

 points in New England it is attacking large trees. Inspection of 

 nursery stock for blister rust is largely futile since the rust often in- 

 cubates in pine tissue for many years before becoming apparent by 

 distorting the growth or by fruiting. According to Ravn this incuba- 

 tion period may be as long as 20 years. As alternate hosts the black 

 currants, both wild and cultivated, are particularly subject to the 

 disease, and in areas of general infection are reliable indicators of its 

 presence. On Ribes the disease is generally prevalent throughout 

 New England, which means that the actual infection of pine is much 

 more general than is shown at present. 



1 7:251. 1917. 



