42 Rhodora [Marca 
as high as mediacid. The orchids, Habenaria (Limnorchis) hyper- 
borea and Cypripedium hirsutum (reginae), and also the typical 
calcareous soil plant, Parnassia caroliniana, grow in the alkaline 
water. Pyrola secunda was noted on a hummock with minimacid 
reaction; while on the more acid ones were found Aspidium spinu- 
losum, A. Boottii, Clintonia borealis, Cypripedium acaule, and Cornus 
canadensis, all plants which normally seem to favor highly acid 
conditions. 
In the Knapp swamp, 5 km. west of St. Johnsbury, the conditions 
proved to be similar to the above. The water ranges from minimacid 
to neutral, and down in moss saturated with this water and sharing 
its reaction grow sparingly the rare orchids, Cypripedium arietinum 
and Calypso bulbosa, which can thus be classed, on the basis of actual 
test, as species of circumneutral soil. Three ericaceous plants, 
Pyrola secunda var. obtusata, Moneses uniflora and Ledum groen- 
landicum grow here, in hummocks with minimacid reaction, and the 
orchid, Cypripedium parviflorum, is abundant in muck with the same 
acidity. At one point a colony of Cornus canadensis was noted within 
10 centimeters of the Calypso-bearing moss, which suggested that 
it might at times withstand minimacid conditions; but actual test 
showed it to have around its roots subacid material: thus the acidity 
may vary 10-fold or more within a few centimeters, and the yegeta- 
tion develop accordingly. In pine woods around this swamp the 
orchids, Cypripedium arietinum, Epipactis tesselata, and Habenaria 
(Lysias) Hookeri are abundantly developed, and their soils, repre- 
senting acid upland peat partially neutralized by underlying cal- 
careous glacial drift, show subacid to minimacid reactions. 
In a swamp in the town of Peacham, further west, the conditions 
are not unlike those just described, but the flora is even richer. Here 
the water was found to be neutral to minimalkaline, and in it grows 
Caltha palustris, which usually seeks circumneutral waters. In 
muck with minimacid reaction was noted Smilacina stellata, and the 
tall Habenarias. Hummocks of sphagnum are here prominent and, 
as they possess the usual mediacid reaction, a number of Ericaceae 
grow upon them. The beautiful pink Pyrola asarifolia var. incar- 
nata (P. uliginosa of some authors) is abundant in this situation, 
the acidity of its soil thus contrasting sharply with that of the typical 
form of the species, which, as noted. in the description of Lake Wil- 
loughby, grows there in neutral soil. Others noted are Pyrola secunda 
