94 THE EVOLUTION OF PLANTS 



It has already been pointed out that the 

 nearest affinities of the Bennettitese were clearly 

 with Dicotyledons. The particular family with 

 which they seem to have most in common is that 

 of the Magnoliacese, to which the stately Tulip- 

 tree and many other beautiful trees and shrubs 

 belong. In this order the numerous, free per- 

 ianth-leaves, not usually distinguished into calyx 

 and corolla, their frequent spiral arrangement, the 

 hypogynous stamens (inserted directly on the 

 receptacle below the gynseceum), the often 

 elongated axis of the whole flower, and especi- 

 ally the long, cone-like receptacle, with its nu- 

 merous carpels, all suggest comparison with the 

 fossil forms. The resemblance extends in a 

 greater or less degree to other related families, 

 such as our familiar Ranunculacese, and the 

 Nymphseacese (Water-lilies). It is interesting 

 to recall that Drimys (Winter's Bark), a member 

 of the Magnoliacese, and two or three plants of 

 allied families, are the only Dicotyledons which 

 are known to have wood of the same simple 

 structure as the Gymnosperms. This group of 

 families has been regarded as primitive by many 

 botanists; there is evidence for the presence of 

 Magnoliacese in Cretaceous rocks. It must, 

 however, be admitted that the union of the 

 stamens into a tube, so characteristic of the 

 Bennettitean flower, is quite unlike anything we 



