PREFACE 



The second part of "An Introduction to Palynology" deals, as was orig- 

 inally planned, with pollen and spore morphology in the Gymnospermae, 

 Pteridophyta, and Bryophyta. Although the illustrations and most parts 

 of the text were ready for printing in the autumn of 1956, the completion 

 of the text had to be somewhat postponed on account of my absence abroad 

 for several months. It was accordingly decided to publish the second part 

 in two instalments: thus, the present volume (Vol. II) consists mainly of 

 illustrations, whereas the following volume (Vol. Ill) will provide the related 

 text. 



Most of the illustrations are palynograms drawn after the author's origi- 

 nals by Anna-Lisa Nilsson. They depict, in a standardized manner, a 

 pollen grain or spore in polar and/or lateral view, together with its sporo- 

 derm stratification and other details. It should be emphasized, however, 

 that the sporoderm stratification details merely hint at the great array of 

 patterns and layers which exist. Pending thorough morphological investiga- 

 tions, the proper interpretation of these layers etc. is still, in many 

 cases, largely conjectural. 



Besides the palynograms, some photomicrographs and electron micro- 

 graphs of very thin sections through spore walls are included. Stimulated 

 by my eminent friend. Dr. R. W. Kolbe, the microscopist and diatom 

 specialist, I tentatively took up — in the late nineteen-forties— electron 

 microscopy as an aid in sporoderm research. These studies have been 

 continued, with better technique and greater success, by Dr. Barbro 

 Afzelius, to whom I am indebted for the electron micrographs here re- 

 produced (with the exception of those of PI. IV and V, which were put at 

 my disposal by Dr. D. von V^ettstein) and for a chapter (pp. 125-134) on 

 the application of new microscopical techniques in palynological research. 

 Another chapter (pp. 135-147), by J. Radwan Praglowski, deals with the 

 technique of making very thin sections from spore material embedded in 

 plastic. As shown by Fig. 1 (p. 2), this technique can also be applied in the 

 study of very old (Palaeozoic etc.) spores. 



In conformity with Vol. I, the present volume has been prepared under 

 the auspices of the Swedish Natural Science Research Council. Help and 

 support of various kinds received from other sources will be duly acknowl- 

 edged in Vol. III. 



Palynological Laboratory, 



Stockholm -Bromma, July 1957. G.E, 



