226 Part III. Chapter 3. 
Uniola longifolia Scribn. 
Poa Chapmaniana Scribn. 
Erianthus alopecuroides L. 
» contortus Ell. 
» brevibarbis Michx. | Decumaria barbara L. 
Andropogon argyraeus Schult. Baptisia alba L. 
» Elliottiii Chapm. Aralia spinosa L. 
Paspalum purpurascens El. (= P. Ptilimnium capillaceum Michx. (= Dis- 
Boscianum Fluegge). copleura capillacea). 
Panicum gibbum EIl. (= Sacciolepis ' Phlox amoena Sims. 
gibba EIl.). Melothria pendula L. 
» viscidum EIl. Liatris (Lacinaria) graminifolia Walt. 
Danthonia sericea Nutt. Helianthus angustifolius L. 
3. Southern Atlantic States and Mississippi Valley. 
We now come to the difficult question of the probable past history of the 
lower austral plants which occur today in the Appalachian region. In studying 
this floral element, one soon reaches the conclusion that it comprises species 
which are markediy different not only in their systematic relationships, present 
distribution in the region and probable past history, but even, to a consider- 
able degree, in their ecologic constitution. | 
Neotropie Elements. A most pronounced element consists of plants of 
probably neotropic origin, which made their first appearance, as we have 
seen, in the Appalachian region in geologically very modern times, prob- 
ably after the close of the glacial epoch. The following list embraces species 
‚which probably from their distribution elsewhere, or from their affinities, are 
most likely to have had this history. 
Erianthus alopecuroides L. - | Yucca filamentosa L. 
» brevibarbis Michx. ı Agave virginica L. 
» _ _contortus EIl. ı Pogonia divaricata L. 
'Andropogon argyraeus Schult.  Phoradendron flavescens Pursh. 
> Elliottii Chapm. | Asimina parviflora Michx. 
Panicum  viscidum EIl. (= P. scopa-  Cocculus (Cebatha) carolinus L. 
rium Lam.).  Schrankia (Morongia) angustata Torf. 
Muhlenbergia capillaris Lam. [ & Gray. 2 
Sporobolus asper Michx. Stylosanthes riparia Kearney. I 
Gymnopogon ambiguus Michx. ' Centrosema (Bradburya) virginiana L ; 
(= G. racemosus Beaur.).  Chrysopogon nutans var. Linnacan 
Triodia cuprea Jaeq. (= Tridens ses- __ (—Sorghastrum LinneanumHack‘. 
_  Jeroides Michx.), ' Paspalum longipedunculatumLeConte. 
 Cyperus echinatus Ell. (— C. Baldwinii | > purpurascens El. (= Bos- 
Torr.). , | cianum Fluegge). a 
Kyllinga pumila Michx. Panicum gibbum EI. (= SacciolepIs 
Xyris communis Kunth. gibba EIl.). 
) 
>Commelina hirtella Vahl. | Panicum angustifolium EIl. 
