22 



Dentaria anomala Euthamia floribunda 



Prunus Gravesii Ludwigiantha brevipes 



It is certainly significant that all these are found in the very- 

 recent glaciated area or on the coastal plain, not one of them in 

 the ancient pine-barren region. This certainly agrees with 

 Willis's conclusion that rarity and youth go hand in hand. It is 

 also true that all the pine-barren, and therefore ancient, endemics, 

 mentioned on page 20 are frequent or even very common in 

 that region. Which seems to prove that commonness and age, 

 like rarity and youth, have some relation to each other, just as 

 Willis has argued. Evolutionary theory, and especially muta- 

 tion, would also lead to the conclusion that rare endemics are 

 recent. 



A rather serious objection to this theory, however, is furnished 

 by Prunus alleghaniensis, Senecio Crawfordii, Kneiffia Allenii, 

 Hibiscus oculiroseus, and Stachys atlantica. All these are cer- 

 tainly not rare, and all are found in geologically the more recent 

 part of our region, while the Hibiscus is a salt-marsh plant and 

 therefore very "new." Some of these extra-pine-barren, and pre- 

 sumably recent endemics, have already occupied more area and 

 become commoner than the pine-barren, and presumably ancient 

 endemics, which is not at all what we should expect if the Willis 

 theory were wholly true. 



While our local endemics seem to fit the theory of Willis 

 better than they do that of Sinnott and Bailey, the fit in both 

 cases leaves much room for doubt. In both cases, too, the 

 theories attempt to explain the results, rather than the under- 

 lying origin of endemism. 



So far as our local endemics are concerned a few can be dis- 

 missed, as to their origin, by the statement that they are relict 

 endemics. Such seems to be the case with Ludwigiantha 

 brevipes, Amphicarpon Amphicarpon, Calamovilfa brevipilus, 

 Dendrium buxifolium, and Uvularia nitida. In all except the 

 last, the only related species are found in Florida or somewhat 

 to the north of it, there being a considerable break in the distribu- 

 tion along the coast between these widely separated generic 

 outposts. None of the first four have any relatives in the 



