6o2 THE POPULAR SCIENCE MONTHLY. 



which is a fair example of the Malionia group. At the same time 

 it is worthy of note that along with the greater uniformity of the 

 branches is associated the possession of compound leaves having 

 from three to many leaflets. This fact, taken in connection with 

 the circumstance that almost all the other members of the family 

 have the leaves more or less plainly of the palmate type, makes it 

 probable that the ancestor of the barberries had trifoliolate leaves 

 not unlike those often found interspersed among the larger leaves 

 of the multifoliate mahonias and appearing also as the sole form 

 on other species of the same subgenus (compare Figs. 5 and 7). 

 It is significant, moreover, that the mahonias are without the 

 highly developed spines so characteristic of the Euherherides, but 

 depend for protection upon the spiny margins of their evergreen 

 leaflets. 



Thus, whether we consider the approach toward similarity 

 among the branches, the approximation in the type of leaf to that 

 most common in the family, or the absence of specialized spines, 

 we are led to the conclusion that the MahonicB since they exhibit 

 so much less differentiation than the Euherherides, must therefore 

 represent more nearly the primitive features of the genus a con- 

 clusion which is confirmed by such paleontological evidence as 

 we possess. For the five species discovered in the Tertiary for- 

 mation of southern France, northern Italy, and Switzerland are 

 all mahonias, one of them {Berberis helvetica) closely resembling 

 the American holly-leaved mahonia here figured, while others are 

 like forms living at present in China. In view of these facts we 

 shall probably be not far from the truth if we picture to our- 

 selves the ancestral Berberis as being a small bush or underbrush 

 resembling in a general way our evergreen holly, but having 

 in place of each simple leaf a compound one of three leaflets. 

 Almost exactly corresponding to this description is the already 

 mentioned Berberis (Maho7iia) trifoliata of Mexico and the adja- 

 cent regions. 



That the ancestral home of the barberries was most probably 

 in the northern part of North America appears from what is known 

 of the geographical distribution of the species when viewed in the 

 light of the generalizations arrived at by Bentham, Hooker, and 

 Asa Gray regarding the origination of the members of the north 

 temperate flora. We learn from Bentham that "to the great 

 majority of them no primeval antiquity can be ascribed in central 

 or western Europe ; they appear to have come from the East, a 

 considerable number perhaps from western Asia, where their types 

 appear to be more varied, but many also must have made half the 

 tour of the globe. Large American genera have sent out offsets 

 into eastern Asia, which, gradually diminishing in number of 

 species and sometimes slightly modifying their character, have 



