1. Dr. Jan Paulus Lotsy 1867–1931

   • W. A. Goddijn

   In memoriam Pages: I - XX

2. On the species of the taxonomist in its relation to evolution

   • J. P. Lotsy

   OriginalPaper Pages: 1 - 16

3. The progeny of a heteroploid (N. Tabacum x N Rusbyi) x N. Tabacum plant

   • Dontcho Kostoff
   • James Kendall

   OriginalPaper Pages: 17 - 26

4. Zur Kausalanalyse der Kernteilung

   • H. Bleier

   OriginalPaper Pages: 27 - 76

5. Interspecific crosses in the genus dianthus

   • I. Andersson-Kottö

   OriginalPaper Pages: 77 - 112

6. Ring-formation in diploid and polyploid campanula persicifolia

   • A. E. Gairdner
   • C. D. Darlington

   OriginalPaper Pages: 113 - 150

7. Bedeutung der Genetik in der Systematik und Geographie der Pflanzen

   • A. Zämelis

   OriginalPaper Pages: 151 - 182

8. The chromosome constitution of Cardamine pratensis and Verbascum phoeniceum

   • W. J. C. Lawrence

   OriginalPaper Pages: 183 - 208