104 Trans. Acad. Sct. 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- 
iow blossoms of Selenia aurea give a truly golden tint 
tothe surface. A little later it assumes a somewhat paler 
hue, as the lemon-colored flowers of Sedum Nuttallianum 
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 
