INDEX TO VOLUME VIII 
533 
Uredopeltis, 447 
Uromyces, 236 
Urtica gracilis, 397 
Urticaceae, 331, 387 
Urticales, floral anatomy of the, 386 
Urticastrum, unusual rusts on Nyssa and, 
442; divaricatum, 444 
Vacciniaceae, 330 
Vachellia Farnesiana, 194 
Variations in the osmotic concentration of 
the guard cells during the opening and 
closing of stomata, 30 
Vascular anatomy of dimerous and trime- 
rous^ seedlings of Phaseolus vulgaris, 63; 
of hemitrimerous seedlings of Phaseolus 
vulgaris, 375 
Vein-islets in leaves of certain plants as an 
age determinant, area of, 433 
Venturia, 319 
Verbascum Lychnitis, 31 
Veronica incana, 31 
Violet, pollen of, 471; stylar canal of, 475 
Vitamines, amino-compounds, and salts on 
hydration, water deficit and the action 
of, 296 
Vitis, pollen tubes of, 474; vulpina, leaves 
of, 433 
Wallflower, pollen of, 471 
Wann, Frank B. The fixation of free 
nitrogen by green plants, i 
Water deficit and the action of vitamines, 
amino-compounds, and salts on hydra- 
tion, 296 
Wheat, influence of temperature on the 
relations between nutrient salt propor- 
tions and the early growth of, 59 
WiELAND, G. R. Monocarpy and pseudo- 
monocarpy in the cycadeoids, 218 
WiGGANs, R. G. Variations in the osmotic 
concentration of the guard cells during 
the opening and closing of stomata, 30 
Willow, 199 
Wissadula holosericea, 200; lozani, 196; peri- 
plocifolia, 196 
Yucca, igS', filamentosa, 218 
Zamia, pollen of, 472; Skinneri, pollen of, 
472 
Zea Mays, 207; Aspergillus on, 118, 121; 
pollen tubes of, 474 
Zehrina pendula, 33, 34, 164 
Zostera, pollen of, 473 
