Stout—Vegetation of a Typical Wild Hay Meadow. 441 
The plants that give character to this marsh vegetation pos¬ 
sess, we may say, the same general appearances and habit of 
growth and hence should be competitors. Yet if we analyze 
their adaptations further we are forced to give up any such 
general conclusion. 
To illustrate: There are, in spite of the same general grass¬ 
like habit of growth, marked anatomical differences already 
mentioned between Car ex stricta and Calamagrostis canadensis. 
Yet as shown in plate 19 there is a tendency for both to oc¬ 
cupy the same territory. One would say at first thought that 
these two species are close competitors yet the mode of root and 
rhizome growth, the vertical stratification, and the seasonable 
development really provide two different environments for the 
two plants altho they may stand side by side. 
A plant society may be not so much a collection of plants of 
various species which are adapted to the same conditions as 
an association of species which are adapted in a different 
fashion to the same locality. This fact has not been sufficiently 
recognized in many ecological studies, but has been most clearly 
pointed out by Yapp in his studies of marsh vegetation in Eng¬ 
land. 
One of the most difficult points in solving the problems of 
plant adaptation in this marsh meadow is the mutual exclusive¬ 
ness of Car ex stricta and Car ex aquatilis. Large numbers of 
rhizomes, roots, and vegetative shoots were examined as to 
structure and general habit of growth. This afforded no evi¬ 
dence as to why there should be such a marked differential dis¬ 
tribution with such apparently slight differences in the en¬ 
vironment. The solution does not seem to be with the differ¬ 
ences in the vegetative habit or in the anatomy. Yet it must 
he said that we know very little of the root and rhizome habit 
of the sedges and grasses. We need detailed studies of vari¬ 
ous root and rhizome systems and the influences which deter¬ 
mine them. 
The evidence afforded by the distribution of these species in 
the marsh meadow studied seems conclusive that Carex aqua- 
tilus, Carex riparia, Typha latifolia, Scirpus validus and Carex 
