78 BULLETIN OF THE 



Tripsacum dactyloides and Pycnanthemum lanceolatum. 3. Four 

 Mile run, half way to Alexandria, not yet sufficiently explored, in- 

 cluding the vicinity of Fort Scott to the northwest, where Clematis 

 ochroleuca and Asclepias quadrifolia may be collected ; and, 4. 

 Hunting creek, a large estuary below Alexandria, including Ca- 

 meron run, the stream which debouches into it, with its tributaries, 

 Back Lick run and Holmes run, which unite to form it. Here 

 have been found, at various points, Clematis ochroleuca, Gonolobus 

 hirsutus, Itea Virginica, Geranium columbinum, Micranthemum 

 Nuttallii, Habenaria virescens, Quercus macrocarpa, Carex gracil- 

 lima, Geum strictum, Galium asprellum, and very many other rare 

 plants. 



On the left bank of the lower Potomac the chief locality of in- 

 terest is a large wooded area below the Government Hospital for 

 the Insane. This has proved a rich hunting ground for the botanist, 

 and has yielded Carex pallescens, Carex Woodii, Gonolobus hirsutus, 

 Silene armeria, Parietaria Pennsylvania, Myosotis arvensis, Scutel- 

 laria nervosa, &c, &c. Asplenium angustifolium is known only at 

 Marshall Hall, where it has been reported by Mr. 0. M. Bryan, 

 while opposite Fort Foote Mr. Zumbrock has found Myriophyllum 

 spicatum, and opposite Alexandria Professor Comstock and Miss 

 Willets have discovered Plantago cordata. 



4. The Terra Cotta Region. 



This embraces some low grounds and undulating barrens near 

 the terra cotta works, at Terra Cotta Station, on the Metropolitan 

 Branch of the Baltimore and Ohio railroad, three miles from the 

 city, and also a small swamp a quarter of a mile beyond, and to 

 the eastward. Here on the dry ground have been found Onosmo- 

 diuvi Virginianum, Lespedeza Stuvei, Clitoria Mariana, and Habe- 

 naria lacera ; and in the swamp Aster cestivus, Solida stricta, 

 Woodwardia Virginica, Asclepias rubra, Poterium Canadense, and 

 numerous other plants rare or absent in other localities. 



5. The Reform School Region. 



This locality is very limited in extent, but has proved one of the 

 most fertile in botanical rarities. Its nucleus consists of a little 

 swampy spot a short distance to the south of the National Reform 

 School, in which is located a beautiful spring ; but the woody 



