INDEX TO AMERICAN BOTANICAL LITERATURE ° 561 
Harris, J. A. Physical chemistry in the service of phytogeography. 
‘Science II. 46: 25-30. 13 Jl 1917. 
Harvey, R. B., & True, R. H. The influence of light and chlorophyll 
formation on the minimum toxic concentration of magnesium nitrate 
for the squash. Am. Jour. Bot. 4: 407-410. f. r, 2. Jl 1917. 
Hawkins, L. A.. & Stevens, N. E. E£ndothia pigments—I. Am. 
Jour. Bot. 4: 336-353. f. 1-6. 29 Je 1917. 
Hedgcock, G. G., & Hunt, N. R. New species of Peridermium. My- 
cologia 9: 239-240. 30 Jl 1917. 
Includes Peridermium ipomoeae, P. terebinthinaceae, P. helianthi, P. fragile, and 
P. minutum, spp. nov. 
Hodgson, R. W. Citrus blast—a new bacterial disease. Calif. State 
Comm. Hort. ie Bull. 6: 229-233. f. 58, 59- J 1917. 
Bacterium citrarefacien 
Hollick, A. Additional notes on the botany of the Silver Lake basin. 
Proc. Staten Island Assoc. Arts and Science 6: 67, 68. f.7, 2. 9 
My 1917 
House, H. D. Ornamental shade trees and their care. Am. Forest. 
23: 414-418. Jl 1917. [Illust.] 
_ Hume, A. N., & Sloan, S.L. Characteristics of quack grass (Agropyron 
_ repens) and western wheat grass (Agropyron occidentale Scribn.), 
with special emphasis on the eradication of quack grass. S. Dakota 
Agr. Exp. Sta. Bull. 170: 497-524. D 1916. [Illust.] 
Johnson, L. The history and legal phases of the smoke problem. Bull. 
Am. Inst. Mining Eng. 125: 893-906. My 1917. 
Kennedy, P. B. New grasses from California, 1. Phalarts sienoptera 
Hack. Univ. Calif. Publ. Agr. 3: 1-9. pl. 1-8. 13 J1 1917 
Kern, F. D. North American species of Puccinia on Carex. Myco- 
logia 9: 205-238. 30 Jl 191 
Includes Puccinia Kellermanii, P. piney P. eminens, spp. nov. and Puccinia 
urticata, P. lysimachiata and P. asterum, comb. n 
, L. O. A method of sbtaietiie: sicedaat sporulation in cul- 
sive of Macrosporium solani E. & M. Torreya 17: 123. 18 Jl 
1917. 
Lee, H. N., & Smith, E. M. Douglas fir fibre with special reference to 
length. ee & Paper Mag. Canada 15: 709-713. pl. 1. f. I-3. 
26 Jli19 
Lloyd, C. a pe: no. 64. 1-4.f.985-991. My 1917; Letter No. 65. 
1-16. Mr £917. 
No. 64 includes notes on different species of Xylaria 
Lloyd, C. G. Mycological notes. 47: Sie 666, f. 933-960 + portrait. 
Ap 1917. 
