18 



ENDEMISM IN THE FLORA OF THE VICINITY OF 



NEW YORK* 



By Norman Taylor 



Of the 2,038 native species in the flora near New Yorkf 

 twenty-two or something over one per cent, are endemic, which, 

 as here considered, means that they are found nowhere else in 

 the world. The endemics are as follows 4 



Sporohulus Torreyanus Hypericum Bissellii 



Savastana Nashii Hibiscus oculiroseus 

 Amphicarpon Amphicarpon Kneiffia Allenii 



Calamovilfa hrevipilus Ludwigiantha brevipes 



Juncus caesariensis Pyrola oxypetala 



Uvularia nitida Dendrium buxifoUum 



Salix squamata Stachys atlantica 



Dentaria incisifolia Eupatorium resinosum 



Dentaria anomala Euihamia floribunda 



Prunus Gravesii Helianthus Dalyi 



Primus alleghaniensis Senecio Crawfordii 



The causes of this endemism are very obscure; perhaps in the 

 very nature of the case there may be a considerable element of 

 chance in it. Some things stand out in connection with our 

 local endemics however, that may throw light on the problem, 

 and it seems certain that a number of related subjects should 

 catch more or less direct illumination in the course of such a study. 



It has been argued by Sinnott and Bailey that endemism is a 

 criterion, at least to a considerable extent, of the antiquity of a 

 flora. Their reasons for this have been so clearly and so recently 

 set forth in the Annals of Botany and in the American Journal of 



* Contributions from the Brooklyn Botanic Garden No. 12. 



t Nomenclature, and the range considered, the same as in the writer's "Flora of 

 the Vicinity of New York: A Contribution to Plant Geography." Mem. New 

 York Bot. Gard. 5: 1-688. 1915. 



X It will be seen that the Ust differs from that in Mem. New York Bot. Gard. 5: 

 32, by the inclusion of Prunus alleghaniensis and exclusion of Vaccinium caesariensis. 

 The first has been found in a few Pennsylvania counties just outside the range, 

 the second now appears to extend south of our area. 



