1202 
Journal of Agricultural Research 
Vol. V 
Peronospora —Continued. Page 
ficariae— 
parasite of Ranunculus ficaria . 64,67 
perennial mycelium in.64,67 
grisea, parasite of Veronica lederaefolia ... 59,67,68 
parasite of Lepidium virginicum .60-62,67 
parasitica — 
perennial mycelium in.60-62,67 
rumicis, parasite of Rumax acetosa . 67 
schachtii, parasite of Beta vulgaris . 59,67 
viciae — 
parasite of Vicia sepium .67,64-65 
perennial mycelium in. 64-65,67 
Persea gratissima, host fruit of Ceratitis capi- 
tata . 657 
Petrography of Some North Carolina Soils and 
Its Relation to Their Fertilizer Require- 
ments (paper). 569-582 
PezoPorus tenthredinarum, parasite of Profe- 
nusa collaris . 527 
Phaseolus vulgaris — 
absorption of boron by.. 883-885 
analysis of seeds and seedlings of. 452 
effect of sulphur on growth of. 238-239 
translocation of mineral constituents of.. 450-454 
Phleum — 
asperum, host plant of Puccinia grammis 
avenae ... 213 
pratense, host plant of Puccinia phleipra- 
tensis . 212 
Phalaris canariensis, host plant of Puccinia 
graminis avenae . 212-213 
Phoma betae, histological relations to seedlings 
of Beta vulgaris . 55-58 
Physical factors, relation to transpiration.. 585-623 
Phytop hthora — 
infestans — 
development of epidemics of.S9-92 
epidemics of, caused by infected seed po¬ 
tatoes. 80-85 
hibernation of, in Irish potato. 71-102 
infection renewed by soil-borne conidia of. 97-98 
influence of temperature on growth of... 77-80 
mycelium of in the soil. 96 
origin of.96-97 
parasite of Solanum tuberosum . 59,67,183 
perpetuation of. 97 
relation of perennial mycelium in species 
of Peronosporaceae to. 59-70 
resting spores of.98-99 
omnivor a, effect of low temperature on. 654 
Pierce, W. D. (paper), A New Interpretation 
of the Relationships of Temperature and 
Humidity to Insect Development. 1183-1191 
Pig, poisoning of, by cottonseed.489-493 
Pine. See Pinus. 
Pinus — 
contorta — 
host plant of— 
Peridermium filamentosum . 783 
Peridermium pyriforme . 133,289-290 
divaricata — 
host plant of Peridermium pyriforme ,,. 133,290 
murrayana, host plant of Peridermium mon- 
tanum . 785 
Ponderosa — 
host plant of Peridermium filamen- 
tosum . 133,781 
scopulorum, host plant of Peridermium 
pyriforme . 133,290 
Pinus —Continued. Page 
pungens, host plant of Peridermium pyri¬ 
forme . 133,290 
rigida , host plant of Peridermium pyri¬ 
forme . 133,289,290 
Pisum — 
arvense, effect of alkali salts on growth 
of. 22-24,25ft 
sativum — 
absorption of boron by.884-885 
effect of sulphur on growth of. 241-242 
Pitz, W. (paper), Effect of Elemental Sulphur 
and Calcium Sulphate on Certain of the 
Higher and Lower Forms of Plant Life.. 771-780 
Plasmopara — 
cubensis , parasite of Cucumis sativus . 259 
halstedii — 
parasite of Helianthus divaricatus .65-66,67 
perennial mycelium in. 65-67 
pygmaea, parasite of Hepatica acutiloba .59,67 
viticola, parasite of Vitis vinifera . 67 
Plenodomus fuscomaculans — 
conditions of growth and reproduction of. 720-764 
effect of— 
acidity and alkalinity on. 734-73 7 
aeration on. 727-730 
air circulation on. 724 
change of intensity of a factor on. 754~7S8 
humidity in. 730-734 
light on. 720-725 
quality of food on. 742-754 
quantity of food on. 73 7-742 
temperature on. 725-727 
growth of. 713-769 
parasite of Malus sylvestris . 713 
pycnidium formation of. 713-769 
Plowrightia morbosa , effect of low temperature 
on. 652 
Plum. See Prunus. 
Plummer, J. K. (paper), Petrography of Some 
North Carolina Soils and Its Relation to 
their Fertilizer Requirements. 569-582 
Poa — 
compressor host plant of Comandra umbel- 
lata . 134 
pratensis, host plant of Comandra umbel- 
lata . 134 
Pocketed heartrot. See Honeycomb heartrot. 
Pod, inheritance of length of, in certain 
crosses.405-420 
Pool, V. W., and McKay, M. B. {paper), Rela¬ 
tion of Stomatal Movement to Infection by 
Cercospora beticola. 1011-1038 
Populus tremuloidesy host plant of Comandra 
umbellata. . 134 
Potassium salts, effect on plant growth.,. 5-6, i6ff 
Potato— 
beetle, Colorado. See Leptmotarsa decemti- 
neata, 
Irish. See Solanum tuberosum. 
sweet. See Ipomoea batatas. 
tuber-rots. 183-210 
Potentilla monspeliensis, host plant of Coman¬ 
dra umbellata . 134 
Pritchard, F. P., and Hubbard, P. (paper). 
Effect of Controllable Variables upon the 
Penetration Test for Asphalts and Asphalt 
Cements. 805-818 
