104 Trans. Acad. Sci. of St. Louis. 



Narrow and linear leafed plants are strikingly predom- 

 inant in these barrens, broad and large leafed species be- 

 ing indeed entirely absent from the typical portions. This 

 is of course plainly a case of adaptation to environment, 

 such species being better able to resist the scorching sun 

 and drouth to which they are subjected. Another notice- 

 able peculiarity, perhaps not so easily explained, is the 

 predominance of yellow-flowered plants. Possibly this 

 is more apparent than real, however, from the fact that 

 most of the common species with conspicuous flowers have 

 petals of this color. Early in the spring the bright yel- 

 low blossoms of Selenia a/urea give a truly golden tint 

 to the surface. A little later it assumes a somewhat paler 

 hue, as the lemon-colored flowers of Sedum Niittallianum 

 come into evidence over a large part of the area. As the 

 season advances the slender scapes of Coreopsis lance- 

 olata and the taller branching stems of C. tinctoria bear a 

 wealth of richly tinted blossoms, conspicuous from afar, 

 like the gold of some fabled Ophir or Eldorado. 



Most of the plants peculiar to the barrens are strictly 

 limited in their range, seldom being found more than a 

 few feet beyond the chert outcrop; and it is only over 

 very limited areas that they are able to maintain undis- 

 puted possession and keep back the hordes of the more 

 hardy races that press upon them from all sides, invading 

 their territory wherever a little greater accumulation of 

 soil exists, as a breach in the rocky barrier that defends 

 them. 



The amount of soil varies greatly in different parts of 

 the barrens, patches of absolutely naked rock, where no 

 form of vegetation can maintain itself, alternating with 

 small areas upon which a deposit of soil and gravel sev- 

 eral inches or even feet in thickness sustains a growth of 

 shrubs and stunted trees, in addition to the herbaceous 

 species. 



The ligneous plants are limited chiefly to a series of 

 low knolls or mounds, that constitute a very striking and 

 peculiar feature of the region, and one that stands in 



