Natural History of District of Columbia — McAtee 103 



ently inhabits only rocky floodplains, that being Baptisia 

 australis. which has been collected at Williamsport, Great, 

 Stnbblefield and Little Falls. 



The floodplain of the Potomac at the latter locality yields 

 a very thorough and interesting mixture of lowland and high- 

 land forms. Ward (Flora, pp. 21-22) has commented upon 

 the diversity of conditions and richness of the flora of the 

 Chain Bridge Flats, but has not forestalled the usefulness 

 of a tabulation of the most interesting plants and their rela- 

 tion to the Coastal Plain and Piedmont Horas. 



CHARACTERISTIC PLANTS OF THE CHAIN BRIDGE FLATS, 

 WITH NOTES ON THE DISTRIBUTIONAL RELATION- 

 SHIPS OF SOME OF THEM. 



Echinodorus radicans 



Coastal '" 

 Sagittaria rigida 

 Andropogon furcatus 

 Paspalum laeve 



Coastal 

 Panicum laxiflorum 



Coastal 

 Eragrostis hypnoides 

 frankii 

 Piedmont 

 Scirpus debilis 



Eleocharis palustris glaucescens 

 Carex comosa 

 lupulina 

 hystricina 

 Piedmont 

 Allium cernum 

 Piedmont 

 Vagnera stellata 

 Piedmont 

 Ibidium plantagineum 



Piedmont 

 Salix interior 



Piedmont 

 wardi 

 cordata 

 Piedmont 

 Quercus prinoides 



Polygonum amphibium 

 Paronychia dichotoma 



Piedmont 

 Brasenia schreberi 

 Radicula sessiliflora 



Coastal 

 Meibomia marylandica 



obtusa 

 Lathyrus venosus 



Piedmont 

 Ceanothus ovatus 



Piedmont 

 Vitis rupestris 



Piedmont 

 Elatine americana 



Piedmont 

 Ammania Koehnei 



Coastal 

 Lythrum alatum 

 Decodon verticillatus 

 KneifBa linearis 



Coastal 

 Samolus floribundus 

 Steironema quadriflorum 



Piedmont 

 Hydrophyllum canadense 



Piedmont 

 Phacelia covillei 



Piedmont 



" Sucli notation applies only to one (the immediately preceding) species. 



