AMERICAN MIDLAND NATURALIST 127 
The two most interesting points in Mr. Skeels’ account are— 
first, that at the Mill Creek station that he writes of, the species 
occurs in two very different conditions, yet in close proximity to 
each other; for it is a sphagnum bog plant along the base of a 
chain of hills, and a sandy woods plant a few rods away along the 
summits of these hills. The second point of deep interest is, that 
it is here a sand dune plant. The Grand Rapids and Mill Creek 
region where Mr. Skeels made these ecologic studies, though many 
miles away from what is the present shore of Lake Michigan is but 
an ancient beach of the same lake. The ridges on top of which the 
Lady’s Slipper grows are but old sanddunes of the ancient shore, 
now overgrown with the forest. This Mr. Skeels understands as 
perfectly as I. He also comprehends as clearly that what he lucidly 
calls the sphagnum pockets down at the base of the old sand dunes 
were water pools anciently, until the sphagnum came in and claimed 
possession. He also assures me that swamp huckleberries grow in 
the sphagnum pockets quite plentifully, and black huckleberries 
are a part of the underbrush amid which the plant thrives at the 
summit. The fact that the plant of sandy ridges is only about half 
the height of that of the boggy places below is well worthy of 
remark. 
A recent letter from Mr. Charles K. Dodge of Port Huron, 
Michigan, in which he acknowledges the receipt of my former 
notes on the species, and also refers to my last spring's visit to 
Port Huron, says: ‘‘I wish you had mentioned to me the Cypri- 
pedium acaule. It is a sand dune plant in Huron County, Michigan, 
growing in abundance in shade, between sand ridges, up and down 
their sides, and all over them ; but always in the shade of small 
trees and bushes. About Port Huron, and across the St. Clair 
River in Lambton County, Ontario, it is only occasionally found, 
and in ground that is wet in spring and autumn, but apt to be dry 
in midsummer. I have never met with it in swamps as stated in 
ks." 
On this exceedingly instructive and interesting piece of infor- 
mation I need but remark that Mr. Dodge has for his field the most 
easterly part of southern Michigan, where the sand dunes are those 
of Lake Huron; and they are not the dunes of many ages since, 
but rather recent and close by the lake itself. His west Canadian 
habitat for it in Ontario, is a part of the same Lake Huron shore 
district 
