1550 



PHANEROGAMS. 



been described, but they are all so like the living form that they should 

 probably be united with it. We here have a striking illustration of the 

 wide distribution of a species which has retained its characters both of 

 fruit and leaf quite unchanged through long migrations and an enormous 

 lapse of time. In Europe the tulip-tree, like many of its American 

 associates, seems to have been destroyed by the cold of the glacial 

 period, the Mediterranean cutting off its retreat ; but in America it 

 migrated southward, and returned northward with the amelioration of 

 the climate.'' 



The mainly tropical family of the Anonacece. includes trees and 

 shrubs closely allied to the Magnolias, and the existing American 

 and Malayan genus Anona is represented in the Upper Cretaceous 

 and Tertiary of the United States, while in Europe it is found from 

 the Eocene to the Pliocene. The extra-tropical North American 

 genus Asimina occurs in the Laramie and Eocene of the same 

 regions. The large family of the Ranunculacece is sparingly repre- 

 sented in a fossil state ; thus Clematis has been recorded from the 

 reputed Pliocene of Japan, the Miocene of QEningen, and the 

 Eocene of Croatia, but it is not absolutely certain that the deter- 

 mination is correct. The same remark applies to other Tertiary 

 plants referred to Ranunculus and Helleborus (Helleborites). The 

 names Dewalquea and Debea have been applied to Upper Cretaceous 

 plants considered to belong to this family, although Dr Schenk 

 suggests affinity with the Aroidece. The Water-lilies of the family 



Nymphceacece. date from the Upper Creta- 

 ceous, where we meet with remains of 

 the existing genus Nelumbium, succeeded 

 in the Upper Eocene (Oligocene) by 

 Nymphcea (fig. 141 6). Seeds from the 

 Miocene of Germany, described as Holo- 

 pleura, are considered to be allied to 

 those of the celebrated Victoria, of the 

 African lakes. Other Tertiary types 

 have been referred to extinct genera 

 under the names of Anasctomeria, Nym- 

 phceites, and Carpolithes. Finally, the 

 genus Nuphar is unknown before the 

 Norfolk Forest-bed, where we meet with 

 the existing Yellow Water-lily. 

 Order 6. Rhoedunle. — Of the Papaveracece (Poppies) and Cruci- 

 ferce, constituting this order, the palseontological history is almost a 

 blank, although a few Miocene forms have been referred to them. 

 The CrucifercE include the Cabbage tribe. 



Order 7. CiSTiFLORiE. — This order is of somewhat more palaeon- 

 tological importance. In the Violacece (Violets and Pansies), An- 

 chietea is recorded from the Miocene of Auvergne ; while in the 



Fig. 1416. — Under surface of a 

 leaf of Neln7iibium Dmnasi; from 

 the Upper Eocene of France. One- 

 eighth natural size. (After Saporta.) 



