Nov., 1910.] 
A Cedar Bog in Central Ohio. 
199 
lings of red maple and yellow poplar are close associates. The suc- 
cession is virtually an indeterminate rejuvenation, that is, the habi- 
tat still dominates the formation. The degree of stabilization is still 
one to give expression to xerophytic forms. The physical conditions 
are changing extremely slowly, remain unfavorable to invaders, 
and tend to preserve many of the most important early vegetation 
stages. The persistence and dominance of the cedar formation 
in this latitude follows for these reasons, but partly also on account 
of the predominance of the trees present; for the formation itself 
must be considered as an essential active factor, in furnishing seeds, 
and eliminating diversity. Largely, however, the dominance is an 
adjustment to the available soil water content. A competition with 
seedlings of deciduous trees other than the yellow poplar and red 
maple does not seem to ensue although the light relation is 
favorable. A relation of seed production to ecesis, i. e., to germi- 
nation and establishment, is nowhere obvious. The various species 
of deciduous trees have a larger seed production and more effective 
dissemination contrivances, but so far as the actual number of 
seedlings is concerned the relative absence of them suggests 
some edaphic agency in selective operation. There is some sort of 
correspondence in the arbor vitae, in plasticity of function, or in 
habitat form, to the life relations of the soil. Definite conclusions, 
however, can only be reached by experimental studies. The field 
observations would indicate that the nature of the primeval forest 
of this region did not consist of a combination of trees such as now 
exists on the drier areas described above. The deciduous arbo- 
rescent facies in which the sequence is the development to the 
deciduous climax forest, is at present decidedly a mixture, and 
though a closed formation, yet one whose original members were 
allied more to the northern cedar bogs. 
To Miss F. Detmers the writer is under many obligations for 
aid in the identification of plants. 
