54 INDEX TO AMERICAN BOTANICAL LITERATURE 
Whipple, O. B. Line-selection work .with potatoes. Jour. Agr. 
+ Research 19: 543-573. 1S 1920. 
Whiting, A. L., & Hansen, R. Cross-inoculation studies with nodule 
bacteria of lima beans, navy beans, cowpeas, and others of the 
cowpea group. Soil Sci. 10: 291-300. O 1920. 
Willaman, J. J. Pectin relations of Sclerotinia cinerea. Bot. Gaz. 70: 
221-229. 15S 1920. 
Williams, R. S.  Grimmia (Guembelia) brevirostris,sp. nov. Bryologist 
23: 52; $3: $l. 3: . 17-5 t620. 
Williams, R. S. Calymperaceae of North America. Bull. Torrey 
Club 47: 367-396. pl. 15-17. 20 0 1920. 
Includes 4 new species. 
Wilson, E. H. A phytogeographical sketch of the ligneous vegetation 
of the flora of Formosa. Jour. Arnold Arbor. 2: 25-41. 1920. 
Wilson, I.K. Device for growing large plants in sterile media. Phyto- 
pathology 10: 425-429. f. 1. 1920. 
Wilson, O. T. Crown- hae of alfalfa. Bot. Gaz. 70: 51-68. pl. 7-10. 
24 Jl 1920. 
Winslow, C. E. A., Broadhurst, J., & others. The families and genera 
of the bacteria. Jour. Bacter. 5: 191-229. My 1920. 
Winslow, E. J. The Dorset fern list again. Am. Fern Jour. 10: 
59, 60. 29 Je 1920. 
Wolf, F. A. A little-known vetch disease. Jour. Elisha Mitchell Sci. 
Soc. 36: 72-85. pl. 2-6. S 1920 
Caused by Protocoronospora nigricans Atk. & Edg., of the Melanconiaceae. 
Wright, R. C. Nitrogen economy in the soil as influenced by various 
_ crops grown under control conditions. Soil Sci. ro: 249-289. 
fd. 1-96 © 1920, 
Yates, W. Natural history notes. Jour. and Proc. Hamilton Assoc. 
Sei. 25, 26: 122-124. 1910. 
Notes on Onoclea and Sambucus. 
Youngken, H. W. The comparative morphology, taxonomy and dis- 
tribution of the Myricaceae of the eastern United States. Contr. 
Bot. Lab. Univ. Pennsylvania 4: aise stl 81-90. 1920. 
Includes M. Macfarlanei Youngken, a new hybri 
Zeller, S. M. Humidity in relation to moisture imbibition by wood 
and to spore germination on wood. Ann. Missouri Bot. Gard. 7: 
53-73 pt. 1. FF to20. 
Zon, R. Forests and human progress. Geog. Rev. 9: 139-166. S 1920. 
Zundel, G.L. Some Ustilagineae of the state of Washington. Myco- 
logia 12: il ad 1920. 
