Jennings : A Botanical Survey of Presque Isle. 405 



migrate, both as to distance covered and as to numbers of migrating 

 disseminules, than do species with more southern relationships, as, for 

 instance, Qucrcus velutina, Ulmus americana, Acer sacchariiuim, etc., 

 so that for historical reasons, as well as for reasons of adaptation to a 

 more northern environment, the earlier stages in most of the succes- 

 sions are more largely related to the northeastern conifer forest center, 

 or at least are more northern in their relationship. 



A Systematic Catalogue of the Ferns and Flowering Plants 

 OF Presque Isle, Erie County, Pennsylvania. 



Ophioglossace.e. 

 Ophioglossiim viilgatinn Linnaeus. 

 Botrycliiuin obliquum Muhlenberg. 

 Botryc1iiumvirginianu7n (Linngeus) Swartz. 



Osmundace^. 



Osmufida claytoniana Linnasus. 

 Osinunda spectabilis Willdenow. 



P0LYPODIACE.E. 



Onoclea sensibilis Linnaeus. 

 Woodsia obtusa (Sprengel) Torrey. 

 Dryopteris boottii (Tuckerman) Underwood. 

 Dryopteris spinulosa (Retzius) Kuntze. 

 Dtyopteris spinulosa dilatata (Hoffmansegg) Underwood. 

 Dryopteris spinulosa intermedia (Willdenow) U^nderwood. 

 Dryopteris thelypteris (Linngeus) A. Gray. 

 Polystichum acrostichoides (Michaux) Schott. 



Equisetace.e. 



Equisetiim arvense Linnaeus. 

 Equisetum hyemale Linnaeus. 

 Equisetum sylvaticiun variegatum Schleicher. 

 " Erie, Presque Isle, Garber." '- 



Lycopodiace.^. 



Lycopodium alopeciiroides Linnaeus. 



Gustave Guttenberg, 1879. Specimens in Carnegie Museum 

 Herbarium. 



'^Porter, T. C. "Catalogue of the Rryophyta and Pteridophyta found in Penn- 

 sylvania." Boston, 1904. 



