586 



SCIENCE 



[N. S. Vol. XXVII. No. 695 



The sierra consists of Cordilleras and inter- 

 Andean valleys. The higher regions are 

 spoken of as punas. Agricultural products of 

 the sierra which are grown at moderate eleva- 

 tion and for the most part independent of 

 irrigation are corn, barley and potatoes and 

 similar crops. Descending the rivers toward 

 the Amazon the valleys are fertile and pro- 

 ductive, but upon entering the forest agricul- 

 ture is meager because of the dense growth of 

 vegetation which has not yet been dominated. 



Ralph Arnold, 



Secretary 



THE BOTANICAL SOCIETY OF WASHINGTON 



The forty-seventh regular meeting was held 

 in the seminar room of the Bureau of Plant 

 Industry on Saturday evening, February 29, at 

 8:30 o'clock. Dr. George G. Hedgcock pre- 

 sented a paper entitled " Crown-gall of the 

 Apple." 



A summary was given of observations and 

 studies on the apple crown-gall conducted 

 during the past five years with large experi- 

 ments in nursery plots and orchards contain- 

 ing nearly 100,000 trees; a part of this work 

 was carried on tinder Dr. Hermann von 

 Schrenk, at the Mississippi Valley Laboratory, 

 St. Louis, Missouri. 



The term " crown-gall " as applied to the 

 abnormal growths on the apple tree, includes 

 a number of forms. The two forms known 

 as the " hard " and " soft " crown-gall are 

 fairly distinct from the hairy-root forms. The 

 latter may be considered for the present as a 

 separate disease. 



The crown-gall of the apple occurs in both 

 the hai;d and> soft forms in this country 

 wherever apple trees are grown to a large 

 extent; it is present on seedlings, grafted and 

 budded trees; both forms are closely related 

 to wounds and the formation of callus. Only 

 wounded trees become affected with the dis- 

 ease, indicating that it may enter through the 

 resulting callus, possibly through stimulation 

 by a parasitic organism. The soft form of 

 apple crown-gall is contagious to some extent, 

 and is identical with the disease on the stone 

 fruits, raspberry, blackberry, dewberry, rose. 



pear and possibly chestnut and walnut. The 

 hard form differs in texture and appearance 

 from the soft, and is either not at all, or only 

 slightly, contagious. It may yet be proved 

 that in case of the hard form, the apple tree 

 has been able to resist and largely overcome 

 the disease by healing processes which lower 

 the vitality of the parasitic organism causing 

 it, and that the two forms have one and the 

 same cause. 



The disease is always injurious to the apple 

 tree in case of the soft form, but the effect in 

 case of the hard form may not always be in- 

 jurious except where the disease encircles the 

 tree, interfering with the circulation. In 

 milder forms the tree may overcome the dis- 

 ease. 



Certain varieties, as Wealthy, Wolf Eiver, 

 Yellow Transparent and others, are subject 

 to the hard form of the disease. On the other 

 hand, certain varieties, as Maiden Blush, 

 Eambo, Eed June, Minkler and others, are 

 more subject to the soft form of the disease. 

 The results from experiments indicate the 

 value of selecting scions from healthy trees. 

 Preventive and curative measures were sug- 

 gested for the control of the disease. 



This paper was illustrated with lantern 

 slides. 



Mr. W. F. Wight presented a paper entitled 

 " Some European Botanic Gardens." The 

 paper consisted of a series of illustrations 

 taken by the speaker, showing scenes in nearly 

 all of the leading botanical and public gardens 

 of Europe, and were explained in detail by 

 him. An account was also given of the work 

 and administration of the Kew gardens. 



Haven Metcalf, 

 Corresponding Secretary pro tern. 



THE philosophical SOCIETY OF WASHINGTON 



The 647th meeting was held March 14, 

 1908, Vice-president Day in the chair. 



Professor Prank H. Bigelow, of the IJ. S. 

 Weather Bureau, read a paper entitled 

 " Evaporation Studies at Eeno, Nevada, and 

 at the Salton Sea, Southern California." 



In the preparation for an extensive cam- 

 paign on the evaporation of water over large 



