Harper : Native weeds and their probable origin 353 



Sisyrinckium (several species). 

 ? Smilax rotundifolia L. 

 Juncus effusus L. 



? 



.. 



<< 



• • 



Eragrostis Purshii Schrad. 



Agrostis hiemalis (Walt.) B. S. P. 

 ? Sporobolns vaginaejlorus ( Torr. ) Vasey. 



? Aristida gracilis Ell. 



??iarginatus Rostk. 



bu fortius L. 



tenuis Willd. (and probably Muhlenbergia mexicana (L. ) Trin. (and 



dichotoma Michx. 



others). 

 ? Spit odela poly 'rrhiza (L. ) Schleid. 

 ? Carex lurida Wahl. 



? 



t< 



<< 



perhaps others). 

 Chaetochloa spp. 

 Panicum (several species). 

 ? Syntherisma sanguinah (L.) Nash. 



filiform e (L.) Nash. 



? « 



pall esc ens L. 



festucacea Willd. 



Muhlenbergii Schk. (and probably Paspalum setaceum Michx. (and perhaps 



a few others). 



others). 



? Fimbristylis autumnalis (L.) R. & S. ? Andropogon spp. 



Eleocharis obtusa (Willd.) Schult. (and ? Juniperus communis canadensis Loud .* 



perhaps others). 

 ? Cyperus filiculmis Vahl. 

 Eragrostis pectinacea (Michx.) Steud. 



? Equisetum arvense L. 



? Botrychium obliquum Muhl. (and some 



allied forms). 



In the southeastern states there are many other species in the 

 same category, and a complete list would probably include some- 

 thing like io per cent, of the species of flowering plants supposed 

 to be indigenous in the eastern United States. How to treat 

 these plants in phytogeographical works is therefore an important 

 question. 



If they are indigenous, but now confined to unnatural habitats, 

 the first inquiry that suggests itself is : where did they grow a few 

 hundred years ago, when their present habitats did not exist? 

 Unfortunately, New England and New York were pretty well 

 settled before botany became a science, and by the time Amer- 

 ican botanists began to study vegetation, rather than plants merely, 

 there were nearly as many roads, pastures, clearings, etc., as there 

 are today, so early botanical literature throws little light on the 

 object. Several explanations have been suggested, and each 

 may account for some species, but none will satisfactorily cover 



all #>* 



all 



cases. 



In the first place, it seems to be a common belief among those 

 northeastern botanists who have given any thought to the matter 

 that in prehistoric times all our native weeds occupied natural 



°Penings in the forests, which have now been completely obliter- 



*S«e U. S. Forestry Bull. 55 : //. j. f. 1. I9<>5- This is a shrubby form of 

 JH'iiperus communis, which has gone by several different names in recent years. 



