210 PALEOBOTANY 



At the sixteenth Meeting of Scandi- mcnts are deposited, and be embedded 



navian Naturalists in Oslo in 1916 it in the accumulating peat or ooze and 



received its birth certificate by LEN- preserved. In this way the peat bogs 



NAR r VON POST who, at that occa- and the sediment banks on lake-bot- 



sion, read a paper on the pollen of toms become archives of vcgetational 



forest trees in bogs of southern Sweden, history imprisoning pollen grains. 



The science of pollen analysis became season after season, millennium after 



of age a few years ago, having already millennium. 



made a brilliant record in its childhood A trained pollen analyst, studying 

 and }Outh. This is amply attested by these forest archives, may not only be 

 more than 1 500 publications which able to tell the family or genus to which 

 have been published on the subject to the pollen grains belong but also the 

 date. species, and, in some cases, even the 

 Pollen analysis is essentially founded subspecies. The identification of the 

 on the following facts. At the time of pollen grains is, however, only one side 

 flowering many trees shed great quan- of the matter. Another, and no less 

 titles of pollen. A single birch catkin important, is the interpretation of the 

 mav produce in excess of ten million fossil pollen flora. This is sometimes 

 pollen grains. In general, pollen grains a very difficult problem. Thus a peat 

 are ver\' small, as a rule averaging be- sample may provide hazel nuts but no 

 t^veen one hundredth and one tenth hazel pollen; and bogs within an area 

 of a millimeter in diameter. Easily car- with aspen and poplar predominating, 

 ried by the wind, some of them are may contain much the same pollen 

 transferred into higher regions by ver- flora as bogs of a nearby area with pine 

 tical air currents and remain there for and spruce predominating. Tlie latter 

 davs, weeks, or even months, before case may be explained by the fact that 

 they settle back to earth. In the mean- the exines of aspen and poplar pollen 

 time this "plankton of the air" may grains are so thin that they are pre- 

 have moved over great distances. Green- served only in exceptional cases, whilst 

 land peats contain pollen grains of those of the pine and spruce pollen 

 pine and spruce, that must have been are very resistant to decay. Further- 

 carried at least 100 kilometers (the dis- more, pine and spruce pollen is easily 

 tance of the nearest coniferous forest in carried by the wind and may be scat- 

 Labrador). CHARLES LINDBERGH tered over considerable areas outside 

 trapped pollen grains and spores by of the coniferous region. Therefore, it 

 means of "sky-hooks" during a flight goes without saying that the evidence 

 over Greenland. In 1937, the author of pollen grains sometimes must be 

 collected pollen grains and spores by taken with a grain of salt, 

 means of vacuum cleaners practically The development of pollen analysis 

 the whole way across the Atlantic be- might, in a certain sense, be compared 

 tween Gothenburg and New York, to the development of a river system. 

 Among the pollen grains thus obtained, The Oslo paper was the source and 

 American specimens were found at stimulus. Successively, and in ever in- 

 least as far as 700 kilometers east of creasing numbers, tributaries— coliabo- 

 Newfoundland. For practical purposes rators— joined the main stream, the 

 of pollen analysis, however, such far- course of which was directed by Von 

 travelling grains are of minor impor- Post and his assistants of the Geolog- 

 tance. After their aerial journey the ical Survey of Sweden. At times un- 

 pollen grains may settle on the surface critical overproduction increased the 

 of a bog or lake or in a bay, where sedi- stream more in breadth than in depth. 



