1 96 
The Ohio Naturalist. 
[Vol. XI, No. 1 
are rapidly disappearing as the clearing of the area nears comple- 
tion. The indications are that in a few years the last vestige of 
this interesting aggregation of plants will be destroyed. 
This type of bog is distinctly northern in pts distribution and 
has not been observed by previous writers to occur south of the 
central part of Michigan. The brief time which could be given 
to the locality made a more detailed sti;dy and the mapping of the 
area impracticable. Yet the notes and records made have 
revealed a considerable number of species hitherto supposed to be 
confined to the states north of Ohio. 
In several places the groves of arbor vitae are dense pure 
stands or facies with scarcely any undergrowth. The association 
has only a single vertical layer in which the lowermost branches of 
the component individuals bear a common spacial relation to 
light. The ground is littered with cedar foliage and only occasion- 
ally small sprouts of the chokeberry (Aronia arbutifolia), and 
stunted seedlings of yellow poplar ( Liriodendron tulipifera) or 
small plants of the spice bush (Benzoin aestivale), alders, and 
woodbine are visible; generally there are no members of a subor- 
dinate species other than a few mosses and liverworts. In more 
open stands in which the effects of fire and cuttings are still 
present the arbor vitae is found here in association with the red 
maple (Acer rubrum), yellow poplar, (Liriodendron tulipifera), 
black ash (Fraxinus nigra), white walnut (Juglans cinerea), 
Sycamore (Platanus occidentalis), and wild cherry (Prunus 
serotina). The undergrowth is not only numerous in species but 
of exceptional height and in five layers. The poison sumach 
(Rhus Vernix) reaches frequently a height of twenty-five feet. 
Other members of this structural part of the formation, and 
determining more specifically the physiognomy of the layer, are 
the alders (Alnus incana, A. rugosa), the winter-berry (Ilex 
verticillata), the chokeberry (Aronia arbutifolia), and the round 
leafed dogwood (Cornus circinata). The inferior layers which 
seem to be entirely determined by the density of the mixture of 
facies are really overlapping communities of woodland and bog 
plants. There seems scarcely no relation to habitat factors. 
Seedlings and sprouts occur in all directions, in various degrees 
of abundance, and only the less hardy plants lose ground, thus 
producing examples of an indiscriminate alternation. The spice 
bush (Benzoin aestivale) is only of relatively less importance in 
the (second) stratum of bushes to the red bud (Cercis canadensis) 
and the elderberry (Sambucus canadensis). 
The subordinate position with regard to the taller species is 
occupied by the cinnamon fern (Osmunda einnamomea), the 
meadow rue (Thalictrum dasyearpum), the spikenard (Aralia 
racemosa) , the bladder fern (Cystoptcris bulbifera) , and touch-me- 
not (Impatiens sp.). With them in varying abundance occur 
