ECONOMIC WOODS OF THE UNITED STATES 117 



61 - 62 Tilia, Aesculus: 



Record, Samuel J.: Tier-like Arrangement of the Elements of Certain 

 Woods. Science, 34: 75-77, Jan. 12, 1912. 



* 3 Alnus: 



Bailey, Irving W.: The Relation of the Leaf -trace to the Formation of 

 Compound Rays in the Lower Dicotyledons. Annals of Botany, 25: 97: 225- 

 241, Jan. 1911. 



Oakleaf, Howard B.: The Wood-using Industries of Oregon. Pub. 

 Oregon Conservation Assn., 1911. 



6i Salix: 



Penhallow, D. P. : A Systematic Study of the Salicacese. Am. Naturalist, 

 39:464, Aug. 1905. 



Lamb, George N.: Willows: Their Growth, Use, and Importance. Bui. 

 316, U. S. Forest Service, 1915. 



Detwiler, Samuel B.: The Willows: Identification and Characteristics. 

 Amer. For., 23: 277: 3-10, Jan. 1917. 



Holden, Ruth: Reduction and Reversion in the North American Salicales. 

 Annals of Botany, 26: 165-173, Jan. 1912. 



^Populus: 



Williamson, A. W.: Cottonwood in the Mississippi Valley. Bui. No. 24, 

 U. S. Forest Service, 1913. 



Burgerstein, A. : Diagnostische Merkmale der Markstrahlen von Populus 

 und Salix. Ber. d. deut. bot. Gesellschaft, 29, Nov. 10, 1911. 



Breton-Bonnard, L.: Le Peuplier. Paris, Lucien Laveur, 1903. 

 **Aspen: 



Weigle, W. G., and Frothingham, E. H.: The Aspens: Their Growth and 

 Management. Bui. 93, U. S. Forest Service, 1911. 



