302 HARPER 



southward to the tropics have a noticeable tendency to 

 become weeds. Some of course are known to have been 

 introduced from the tropics, and occur with us only as 

 weeds, but in the case of many which grow in natural 

 habitats like this one there is an indefinable something 

 about their appearance which leads one to suspect that they 

 may not be indigenous. The explanation of this is probably 

 that a species which ranges through several degrees of 

 latitude is usually capable of adjusting itself to different 

 edaphic as well as climatic factors, and is therefore able 

 to encroach on the territory of less tolerant species. 



There is of course another category, of strictly native 

 plants which are now supposed to have a very wide range 

 but will be found on further study to be distinct from the 

 related forms in the tropics. With practice one can usually 

 distinguish the strictly native from the doubtfully native 

 plants without much trouble. 



ELIONURUS H. & B.; Willd., Sp. PI. 4: 941. 1806. 

 (Original spelling Elyonurus.) 



E. tripsacoides H. & B., 1. c. 



Rottbcellia ciliata Nutt., Gen. 1 : 83. 18 18. 



Andropogon Nuttallii Chapm., Fl. 580. i860. 



berrien: In those peculiar Lafayette-less spots already men- 

 tioned several times (see pp. in, 112) southwest of Tif ton. 

 Collected once in a similar place near the southwestern 

 corner of Camden County. 



Also in East Florida, and in the tropics. 



MANISURIS L., Mant. 2 : 164. 1771. 

 M. rugosa (Nutt.) Kuntze, Rev. 2 :78c 1891. 



Rotiboellia cor rugaia Baldw., Am. Jour. Sci. 1:355. 18 19. 

 Moist pine-barrens, etc. ; not common, dooly (1959), worth, 

 berrien, colquitt. Fl. Aug.-Sept. Not known farther 

 inland, but extends coastward to Echols and Charlton 

 Counties (originally discovered in Camden County). 

 South to Florida and west to Texas, in the pine-barrens. 

 Also in Delaware. 



