188 INDEX TO AMERICAN BOTANICAL LITERATURE 
Whetzel, H. H., & Humphrey, H. B. Frederick Kalpin Ravn. Phyto- 
pathology 11: 1-5. Ja 1921. 
Wiegand, K. M. Additional notes on Amelanchier. Rhodora 22: 
146-151. 29 O 1920. 
2 new species and I new combination. 
Wieland, G. R. Recedent lake shores of the Cretaceous. Science II. 
27.537, 538. 3. D 1920. 
Wilson, E. H. The romance of our trees—VI. The magnolias; VII. 
The beeches; VIII. The nut-bearers of the north; IX. Whence 
came our common fruits? X. The Lombardy poplar and the 
- Babylon willow. XI. Trees of columnar growth. Gard. Mag. 31:. 
48-53; II5-119; 194-198; 259-263; 317-320; 381-384. 1920. 
Winslow, C.-E. A., and others. The families and genera of the Bac- 
teria. Jour. Bact. §: 191-229. My 1920. 
Wister, J. C. Notes on the history of the bearded iris. Jour. New 
ork Bot. Gard. 21: 181-191. O 1920. 
Wolden, B. O. The moss and lichen flora of western Emmet County 
[Iowa]. Proc. Iowa Acad. Sci. 26: 259-267. 1919. 
Woodcock, E. F. Observations on the potato disease conditions in 
Michigan for the summer of 1918. Ann. Rep. Michigan Acad. 
Sci. 21: 281-285. Jl 1920 
Woodward, R. W. Panicum albemarlense in Connecticut. Rhodora 
23: 162, 163. | 14 Ja toa. 
Wright, R.C. An apparatus for determining small amounts of carbon 
dioxide. Am. Jour. Bot. 7: 368-370 f. r. 7 D 1920. 
Wyant, Z. N. The influence of various chemical and physical agencies 
upon Bacillus botulinus and its spores. Jour. Bact. 5: 553-557. N 
1920. 
‘Young, L. J. A study in the difference in soil requirements of pine and 
spruce. Ann. Rep. Michigan Acad. Sci. 21: 219-221. Jl 1920. 
Youngken, H. W., & Slothower, G. A. Rhus venenata DC. Am. 
Jour. Pharm. 92: 695-701. O 1920. 
Zeller, S. M. Wood decay in orchard trees in Oregon. Oregon Crop 
Pest and Hort. Rep. 3: 132-138. f. 35-37. 10 Ja 1921. 
Zinn, J. Wheat investigations. Pure lines. Maine Agr. Exp. Sta. 
Bull. 285: 1-48. pl. 1-3. Mr 1920. 
Zon, R. Forests and human progress. Geog. Rev. 9: 139-166. S 
1920. 
