Fee, Everett J. The diatoms in a small Iowa creek. 393

Mogensen, H. Llyod. A contribution to the developmental anatomy of the root of Quercus L. 413

Jensen, Keith F. and Gordon E. Gatherum. Height growth of Scotch pine seedlings in relation to pre-chilling, photoperiod and provenance. 425

Reyes, R. and K.J. Frey. Effect of seeding rates upon survival of genotypes in oat populations. 433

Vasey, Fred W. Age and growth of walleye and sauger in pool 11 of the Mississippi River. 447

Drecktrah, Harold G. and T.A. Brindley. Morphology of the internal reproductive systems of European corn borer. 467

Lersten, Nels R. An annotated bibliography of botanical clearing methods. 481

Dykstra, G.F. and .E. Gatherum. Physiological variation of Scotch pine seedlings in relation to provenance and nitrogen. 487