PALEONTOLOGY. 313 



are the older and the newer dicotyl-stem types; and such a fact best 

 attests the vaHdity of the claim that the study of the cycadeoids has 

 brought into a more normal perspective certain larger factors of 

 dicotyl (as well as gymnosperm) stem evolution. 



Some attention has been given to the limits of fossil evidence, or 

 the negative phases of antecedent relationships of fossil forms to 

 present groups. It appears that a more persistent scanning of the 

 negative or inferable side of the fossil record will prove helpful in 

 gaining a better appreciation of the main course of change. Views 

 have been too nearly restricted to the bare chronologic record. Thus 

 it has been supposed that there was a general absence in the Jurassic 

 and earlier floras, of the higher types of seeds, flowers, foUage, and 

 stems. This view is inadequate. As a later development of the 

 study of the Cycadeoids there has been found within the greater 

 series a striking lesser group of blade-leafed, small-stemmed, small- 

 flowered plants, the Microflorse, now known to have had a world-wide 

 distribution in the Mesozoic. The discovery of this group profoundly 

 affects our views of the probable character of early dicotyl foliage and 

 of fructification. 



The small-flowered Cycadeoids, or Microflorse, show that the early 

 angiospermous flowers may in hke degree have failed to leave a record; 

 and they also invite attention to the theory of polar and upland early 

 angiosperm stocks. The stems of the Microflorse are rarer still than 

 the flowers. A single petrified stem of one of these plants from the 

 early Trias would doubtless reveal structures leading toward the 

 early dicotyl-stem types; yet after nearly twenty years of search in 

 museums and afield not a fragment "with structure conserved has been 

 found. Nevertheless the Cretaceous conifer stems from Kreischer- 

 ville, on Long Island, so satisfactorily investigated by Hollick and 

 Jeffrey some years since, show how stems of the Microflorse must 

 occur and sooner or later be discovered. That these stems had fea- 

 tures similar to those of the better-known Cycadeoids is certain 

 enough; but they varied far more, as indicated by form, foliage, and 

 habitat. 



Similarly, when we turn to the leaf record. Within the Microflorse, 

 despite their unknown stem structure, the Triassic approximations 

 nearest to dicotyledonous plants are discovered. Taking into con- 

 sideration the general leaf types in evidence from the Rhatic to the 

 Lower Cretaceous, it is thus of great interest to find how simple 

 could have been a course of change from the parallel venation of 

 the ancient bladed-leaf types seen in the Microflorse into the magnoli- 

 aceous type of venation. By the drawing apart of the lateral parallel 

 veins in Stangentes-iike leaves with relative increase in vein-size and 

 a correspondent invasion of the marginal net, the typical dicotyled- 

 onous blade would be reached. Vein bulk would thus remain the 



