Harper: Explorations in Georgia 1904 



457 



ijiica, Scirj)?is cylindricus, Xyris Smalliana, Eriocaiilon coiuprcssiim^ 

 Pontcdcria cordata^ Pogonia divaricata^ Brasenia purpurea. Poly gala 

 lutea, Hypericiwi fdsciadaium^ H. aaitifolium^ Rhexia glabella 



piibcscenSy Proscrpinaca p 



Monni 



ana^ Utriadaria pinpiwea, Houstonia roticndifolia, Vibitnuiui niti- 

 dtnn, Sclerolepis nniflora^nd Sericocarpus bifoliatns. Two of these, 

 Anchistea and Mounitra, are reported in Mohr's Plant Life of Ala- 



FlGtTRE 3. "Alligator Pond," in the outlying pine-barrens near Omaha._ May 

 24. The tree in the left foreground is Finns sej'otina, and most of those in the distance 

 are of the same species. Pontederia cordata conspicuous in the foreground. (For a 

 list of some other species observed in the same pond, see Bull. Torrey Club 30: 325. 

 1903-) The demarcation between the pond vegetation and the surrounding shrubbery 

 is much more abrupt here than in typical pine barren ponds, and suggests the glacial 

 lakes of the northern states. 



bama as having been collected by Dr. E. A. Smith \\\ the neigh- 

 boring counties of Russell and Barbour in Alabama. 



Now as for the cause of these outlying pine-ban*ens. The two 

 superficial formations, Lafayette and Columbia, are present, as in 

 the typical pine-barrens and most other parts of the coastal plain, 

 but these rarely if ever determine the topography. The conclusion 

 is irresistible that we have here between the Lafayette and Creta- 

 ceous strata an outlying patch of some Tertiary formation. Dr. 



