INDEX TO VOLUME VIII 
polystachyum, 44; sieherianum, 43; spica- 
tum, 43; typhoideum, 41 
Pennypacker, John Y. (See J. Arthur 
Harris, 63, 339, 375, 425) 
Permeability, the effect upon, of (I) the 
same substance as cation and anion, (II) 
changing the valency of the same ion, 464; 
of plant cells, quantitative study of the 
effect of anions on the, 366; of polyvalent 
cations in combination with polyvalent 
anions, effect upon, 382 
Perotis latifolia, 43 
Pestalozzia, on Sapodilla, 523 
Petunia, pollen of, 479 
Phakopsora, 447 
Phaseolus multiflorus , experiments with, 
291; vulgaris, correlations between ana- 
tomical characters in the seedling of, 
339; interrelationship of the num,ber 
of the two types of vascular bundles 
in the transition zone of the axis of, 
425; normal (dimerous) seedling of, 66; 
trimerous seedling of, 69; vascular anat- 
omy of dimerous and trimerous seedlings 
of, 63; vascular anatomy of hemitrimerous 
seedlings of, 375 
Phlox, pollen of, 472 
Phyllosticta, 320 
Physopella, 447 
Pilobolus, 371 
Pinaceae, 331 
Pine, 198; pollen of, 471, 483; blister rust, 
316 
Pinon, 198 
Pinus Coulteri, 223; edulis, 199; attenuata, 
22 T, ; palustris, 194; taeda, 194 
Piper abalienattim, 213; albicaule, 213; 
brachypus, 213; Diguetianum, 214; dis- 
cophorum, 213; Jaborandi, 212; Mas, 215; 
Muelleri, 213; Neesianum, 213; ovatum, 
213; Rosei, 215; smilacifolium, 213; Tatei, 
213; Thiemeanum, 213; yucatanense, 213; 
Zippelia, 213 
Plant pathology, the relation of, to human 
welfare, 315 
Plantago lanceolata, pollen of, 479; major, 
282 
Platanus, Aspergillus cultures on bark of, 
113; occidentalis , 437 
Poa pratensis, 255 
Poaceae, 328, 331 
Poison ivy, 127, 130; oak, 127, 130, 132, 133; 
of Rhus, 137; vine, 127 
Poison, Rhus, transmission of, from plant 
to person, 238 
Pollen and pollen enzymes, 471 
Polygonaceae, 328; food plants of, 329 
Potato, 257; late blight fungus, 316; losses 
from disease, 315; wart, 316 
Prepinus, 224 
Primula ohconica, 244 
Prosopsis glandulosa, 194 
Protococcus sp., 2, 18, 19, 20, 21, 22 
Protosiphon hotryoides, 2, 18, 19, 20, 21, 22 
Pseudomonocarpy, monocarpy and, in the 
cycadeoids, 218 
Puccinia, 236; coronata, 452; Distichlidia, 
282; glumarum, 523; graminis, 453 
Quantitative study of the effect of anions 
on the permeability of plant cells, 366 
Quercus alba, leaves of, 433; michauxii, 194; 
stellata, 194; virginiana, 197 
Raber, Oran L. a quantitative study of 
the effect of anions on the permeability of 
plant cells, 366; the effect upon' permeabil- 
ity of polyvalent cations in combination 
with polyvalent anions, 382; the effect 
upon permeability of (I) the same sub- 
stance as cation and anion, and (II) 
changing the valency of the same ion, 464 
Ragweed pollen, 473 
Ranales, floral anatomy of, 403 
Ranunculaceae, 330 
Respiration, comparative studies on, XVIII. 
Respiration and antagonism in Elodea, 
458 
Rhododendron, stylar canal of, 475 
Rhus Cotinus, 184; diver siloba, 238; diver- 
siloba, morphology and anatomy of, 179; 
diversiloba, study of, with special refer- 
ence to its toxicity, 127; lobata, 128; 
radicans, 127, 238; Toxicodendron, 127, 
180, 239; var. radicans, 183; venenata, 
248; vernicifera, 137, 181, 244; Vernix, 
137, 188, 239 
Rhus poison, transmission of, from plant to 
person, 238 
Rice smut, 319 
Richardia, pollen of, 472 
Robinia, 27; Pseudo-Acacia, 175 
Root hairs, thick-walled, of Gleditsia and 
related genera, 171 
Root pressure, mechanism of, and its relation 
to sap flow, 369 
