xviii THE CAYUGA FLORA. 



These are: 



Goodyera Menziesii, Populus balsamifera, 



Draba arabisans, Juncus alpinus, var. insignis, 



Saxifraga aizoides, Eleocharis pauciflora, 



Lonicera oblongifolia, Carex gynocrates, (at Savannah), 



Petasites palmata (probably), " capillaris, 



Pinguicula vulgaris, " CEderi. 

 Primula Mistassinica, 



The following apparently have their limit of distribution here but 

 probably extend into the mountainous parts of Pennsylvania. 

 Viola renifolia, Carex longirostris, 



Valeriana sylvatica, " pauciflora, 



Spiranthes Romanzoffiana, China peudula, 



Carex Deweyana, Poa debilis. 



The very remarkable sub-arctic group, — Primula and others, — may 

 have been driven down here by the ice-sheet and have retained their 

 foothold after its recession, finally retreating to the shaded wet walls 

 of the ravines which were then forming, where they now remain, iso- 

 lated from the home of the species. Several species are curiously 

 modified in form and appearance, so as to resemble — according to a 

 well-known biological law, — related species whose center of distribu- 

 tion is in this region. Such is the case with Carya sulcata, Viola 

 renifolia and Juncus alpinus, var. insignis. 



There are also visible traces in our flora of a connection with 

 the Alleghanian plants. The best evidence is in the characteristic, 

 common plants of the dry woods and ridges enumerated under the 

 Lesser Floras. Indeed to any one familiar with the mountains of 

 Virginia the correspondence is most striking. A few rare plants of 

 Alleghanian origin probably find their northwestern limit with or 

 but little north of us. These are Dicentra eximia, Magnolia acu- 

 minata, Prenanthes serpentaria, Deyeuxia Porteri and Rhododen- 

 dron maximum. Hydrangea arborescens, found near Wellsburg on 

 the Chemung R. and even in Warsaw Glen by Dr. Jordan, also by 

 Miss Ross, will probably be found in our flora. There are a consider- 

 able number of species with a general southern range which disappear 

 before they reach our northern limits. I have enumerated fifteen 

 such, the most interesting of which are Negundo aceroides, Agrimo- 

 nia parvijlora, Coreopsis discoidea, Polymnia Uvedalia, Potamogeton 

 obtusifolius, Juncus marginatus and Cyperus Engelmanni. That the 

 Appalachian system has long interposed itself between us and the 

 Coast is evidenced by the few species peculiar to that region which 

 terminate within our limits. Solidago neglecta, var. linoides, and 

 Andromeda liguslrina with possibly Carex glaucodea are the only 

 indigenous species recognized as belonging to that class. 



It is believed that the following local species have not been report- 

 ed from elsewhere in New York : Goodyera Menziesii, Carya sul- 

 cata. Potamogeton obtusifolius, P. Hillii, Carex capillaris, Deyeuxia 

 Porteri, Panicum nervosum, Polygonum nodosum. 



