146 THE AMERICAN BOTANIST 



agreed as to where to draw the line in such matters. In the 

 earlier sense cross pollination or xenogamy meant the trans- 

 fer of pollen from the flowers of one plant to the stigmas of 

 another. It was in this sense that Darwin and other early 

 botanists used the term. It is modern practice which has in- 

 jected the idea that different species of varieties are necessary 

 to cross pollination. This is due very likely to the extension 

 of the meaning of a cross in plant breeding. A sensible rule 

 would be to regard any transfer of pollen from one plant to 

 another as cross pollination, making if necessary a distinction 

 between the crossing of vegetal ively produced plants, between 

 plants of the same species produced from seeds, and between 

 different varieties, species, or members, of different genera. 

 .Many of these phases have no names, but this defect will 

 doubtless be remedied by the name tinkers, now that the mat- 

 ter has been called to their attention. 



Origin of the Dicots. — It is possibly due to the usual 

 arrangement of the species in the Manuals, that the idea pre- 

 vails that the dicots originated from monocots and the latter 

 from the conifers or Gymnosperms. A better understanding 

 of the ancient floras as indicated by their remains in the rocks 

 has shown that the dicots are by no means as recent as we 

 sometimes suppose. It now appears that even in very ancient 

 times there were numerous representatives of the magnolias, 

 barberries, willows, beeches, figs, laurels and myrtles in the 

 world. Moreover, since most of our fossils are by the nature 

 of the case wet ground forms, it seems likely that an immense 

 number of land forms may have perished and left no sign. 

 The family line of the dicots, therefore, runs back to remote 

 ages and instead of joining that of the conifers rather parallels 

 it. The monocots, once thought to be older than the dicots, 

 now appear to be a somewhat modern branch of the latter. 

 It is highly significant that the dicots which in point of struc- 

 ture most resemble the monocots are those same families of 



