276 MORPHOLOGY OF ANGIOSPERMS 



7. Farinales. Restionaceae, Centrolepidaceae, Eriocaula- 

 ceae. Three of the eleven families of the series are thus intro- 

 duced, the first two now being restricted to the southern hemi- 

 sphere, but during the Tertiary ranging through Europe. 



8. Liliales. (Liliaceae, Dioscoreaceae), Juncaceae, Irida- 

 ceae. The last family is the highest member of the series, and 

 its appearance before certain of the lower families is altogether 

 doubtful. 



9. Scitaminales. Musaceae. The series consists of four 

 families, and this one, now confined to the oriental tropics, is 

 recognized as the most primitive. 



10. Orcliidales. Xot represented. , 

 At the end of the Tertiary, therefore, there is reasonable 



evidence as to the existence of all the great Aeries of Monocoty- 

 ledons excepting the highest, and of nearly one-half the fam- 

 ilies. 



DICOTYLEDONS 



Any evidence as to the comparative antiquity of Monocoty- 

 ledons and Dicotyledons is much to be desired, but as yet the 

 historical evidence is not definite, for no undoubted Monocoty- 

 ledon has been recorded from strata older than those in which 

 typical Dicotyledons first occur, and vice versa. The great and 

 sudden prominence of the Dicotyledons in the Upper Cretaceous 

 and Tertiary was long a puzzle, only relieved by the solitary 

 Populus primaeva of the Lower Cretaceous. Comparatively 

 recent studies, however, of contemporaneous beds in the United 

 States and Portugal now regarded as Lower Cretaceous have 

 thrown much light upon the subject, and since 1888 our knowl- 

 edge of the origin of the Dicotyledons has increased rapidly. 

 It should be remembered that the group is largely composed of 

 herbaceous plants, and could not have a fair representation 

 among fossil forms. 



LOWER CRETACEOUS DICOTYLEDONS. The dicotyledonous 

 flora of the Lower Cretaceous was an abundant one, and is of 

 great interest in the history of Dicotyledons. It consists of a 

 plexus of forms, some of which are clearly related to existing 

 Dicotyledons, others are clearly Dicotyledons but with no living 

 representatives, while others are vague in their relationship to 

 Dicotyledons. The few forms that can be referred with any 



