LATER CRETACEOUS AND KAINOZOIC. 205 



habits tropical and warm temperate climates in both 

 hemispheres. Only one species occurs in the United 

 States, BauMnia lunarioides, Gray, found by Dr. Bige- 

 low on the Eio Grande. 



" Hymencea is another of the leguminosae, and inhab- 

 its tropical America. A species of this genus has been 

 found in the Upper Cretaceous of France, but quite dif- 

 ferent from the one before us, in which the leaves are 

 much larger, and the leaflets are united in a common 

 petiole, which is winged ; this is a modification not found 

 in the living species, and one which brings it nearer to 

 BauMnia. 



" But the most surprising discovery yet made is that 

 of a number of quite large helianthoid flowers, which I 

 have called Palceantlms. These are three to four inches 

 in diameter, and exhibit a scaly involucre, enclosing what 

 much resembles a fleshy receptacle with achenia. From 

 the border of this radiate a number of ray florets, one to 

 two inches in length, which are persistent and must have 

 been scarious, like those of Hclichrysum. Though these 

 flowers so much resemble those of the composite, we are 

 not yet warranted in asserting that such is certainly their 

 character. In the Jurassic rocks of Europe and India 

 some flowers not very unlike these have been found, which 

 have been named William sonia, and referred to cycads by 

 Carruthers. A similar fossil has been found in the Cre- 

 taceous rocks of Greenland, and named by Heer William- 

 sonia cretacea, but he questions the reference of the genus 

 to the Cycadeae, and agrees with Nathorst in considering 

 all the species of Williamsonia as parasitic flowers, allied 

 to Brugmansia or Rafflesia. The Marquis of Saporta 

 regards them as monocotyledons, similar to Pandanus. 

 More specimens of the flowers now exhibited will perhaps 

 prove what we can now only regard as probable that 

 the Composite, like the Leguminosce, Magnoliacece, Ce- 

 lastracece, and other highly organised plants, formed part 



