49 



by a stream or spring and here we find still a different 

 association of plants. Besides these Avhich ma^^ be con- 

 sidered as constituting the natural plant covering of 

 the region we have other assoeiations whose advent is 

 determined by the presence of man. Among these we 

 may distinguish, 1st, the weeds of cultivated fields and 

 gardens ; 2nd, the weeds of pastures, roadsides and waste 

 places; 3rd, the plants of abandoned or "turned out" 

 fields, and, 4th, the plants of the second growth woods 

 that ultimately reclothe these abandoned fields. The lob- 

 lolly pine {Fin us Tacda) usually plays the leading part 

 in this f orestization, though with it are associated sweet 

 gum (Liquidaiiihar) black gum ( Nyssa sjjlvatica) , per- 

 simmon {Diospyros) and occasional individuals of nu- 

 merous other trees. 



Ophioglossaceae. 

 jBotrychium biternatum (Lam.) Underw. 



A single specimen, upland pasture, Auburn, (in Underwood 

 Herbarium.) 



Botrychium obliquum Muhl. 



Frequent, creek-bottom woods. 



Botrychium Virginianum (L. ) Sw. 

 Occasional, creek-bottom woods. 



Ophioglossum crotalophoroides Walt. 



Occasional, grassy creek-bottom pastures. 

 OSMUNDACEAE. 



Osmunda cinnamomea L. 



Common, swampy places. 



Osmunda regalis L. 



Common, swamps. 



