1907] Fernald,— Soil Preferences of Alpine Plants 175 
potassic rocks, a few are able to grow, under protest as it were, upon 
the strongly magnesian soil of Mt. Albert; but that another group of 
plants, unknown upon our granitic, gneissic, and schistose mountains 
or on the strongly calcareous mountains and cliffs, are not only re- 
stricted to the strongly magnesian rocks, but there attain a normal 
and often a luxuriant development.’ 
It will be remembered that on the northern edge of Mt. Albert 
(Group Ia) two groups of plants are found; some species ordinarily 
confined to the potassic rocks (feldspathic or micaceous), others gen- 
erally known only from the strongly calcareous soils. Different sec- 
tions of the northern and eastern slopes of the mountain examined 
by Mr. Low showed the rock of the upper or subalpine and alpine 
district to be chiefly hornblende-schist and amphibolite, with occa- 
sional large areas of impure limestone, chloritic slates and schists; and 
gneiss, made up chiefly of orthoclase (potash-feldspar) and hornblende ; 
and as indicated by rock-specimens kindly examined microscopically 
1 It is interesting, in view of the great abundance on the serpentine of Mt. Albert of 
Cerastium arvense, to note that in 1887 Drs. Hollick and Britton called attention to the 
fact that on Staten Island C. arvense, var. oblongifolium ‘* grows abundantly at many 
places on the serpentine hills, and in no other parts of the Island”; and that an analysis 
of the ash of the Staten Island plant showed it to contain ` 
“Silica (SiO,) à ^ : > : ; : . 39.85 
Alumina and Oxide of Iron (Al, O; and Fe, Oj) . ; . 18.58 
Lime (CaO) : : x s : * E e 9.35 
Magnesia (MgO) . : í : ^ 19.79” 
See Hollick & Britton, Bull. Torr. Cl. xiv. 45-50 (1887). 
This is a remarkable amount of magnesia to be present in a plant, the average plants 
of mixed soils deriving from the soil much less magnesia (See Dana, Man. ed. 4, 74). 
As a rock plant, Cerastium arvense is rare in Maine, only one station, on the rocks 
between Cape Cottage and the light-house at Cape Elizabeth, being known personally 
to the writer; and, according to Hitchcock ‘‘Cape Elizabeth is largely composed of 
talcose schist [hydrous silicate of magnesium] "— C. H. Hitchcock, Agr. and Geol. Me., 
Ser. 2, 1861, p. 162 (1861). It will be noticed that in the tables of distribution Cerastium 
arvense is entered in Group I only from the eastern coast of Maine. The stations are 
few, the Duck Islands, etc., and it is not improbable that the plant is there on magnesian 
soil, for Hitchcock records talcose schist and serpentine as largely present along the 
coast of Penobscot Bay and on some of the neighboring islands. (Hitchcock, 1. c., 
162-163). 
Several other plants of low altitudes have been recorded as occurring primarily on 
magnesian soils, but as yet such data in regard to North American plants is unfortunately 
rare. 
In Europe, two much-discussed ferns, Asplenium adulterinum Milde and A. Adiantum 
nigrum, subsp. serpentini (Tausch) Heufler, are clearly demonstrated to grow only on 
serpentine, and on that rock to take the places respectively of A. viride, which prefers 
calcareous rocks, and A. Adiantum nigrum (typical), which is commonly on silicious soils. 
— For discussion see Luerssen, Farnpfl.165-184, 275-281 (1889), also Schimper, Pflanzen- 
Geogr. 103, 104 (1898). : 
2 Low, Geol. Surv. Can., Rep. for 1882-83-84, pt. F. 17, 18 (1884). 
