Seedling emergence and growth responses of dwarf grain sorghum as affected by gibberellic acid. F.P. Gadner and M.J. Kasperbauer. 311

Spherically symmetric charge distributions. B.C. Carlson. 319

Water yield prediction in southern Iowa based on watershed characteristics. Paul R. Nixon and Glenn O. Schwab, 331

An optical density method of measuring phytoplankton standing crop. Lawrence F. Small. 343

Solar radiation an sunshine in Iowa. P.J. Waite and R.H. Shaw. 355

Factors affecting the incidence of reaction tissue in Populus deltoides Bartr. Graeme P. Berlyn. 367