1907] Fernald,— Soil Preferences of Alpine Plants 191 
Solidago multiradiata (Groups II & ^ Senecio pauciflorus (Group II) 
IIT) Cirsium muticum, var. monticola 
Aster foliaceus (Group III) (Group III) 
Erigeron hyssopifolius (Group IT) Taraxacum ceratophorum (Group 
Gnaphalium norvegicum (Group I) II) 
Achillea borealis (Groups II & III) Prenanthes trifoliolata, var. nana 
Petasites trigonophylla (Group I) (Groups I & III) 
Arnica mollis (Groups I & II) 
On these bogs and meadows, it will be noticed, there is a decided 
mingling of the plants which on alpine rocky slopes or on cliffs are 
rarely if ever found associated. 
Similarly, in the valleys of rivers flowing from our higher mountain 
areas fragments or seeds of alpine plants are washed down to the bot- 
tom-lands where there results a mingling of the plants which are 
ordinarily confined to distinct areas and soils. Thus, along the River 
Ste. Anne des Monts, which receives much of the drainage from Mt. 
Albert, Table-top, and the adjacent mountains, we find, on the broad 
alluvial * flats" which are submerged during the freshet periods, such 
plants as Vaccinium ovalifolium (Group 1), V. Vitis-Idaea, var. minus 
(Groups I & IMI), Lychnis alpina (Group HT), Epilobium alpinum 
(Group D) and Deschampsia caespitosa, var. alpina (Group III) 
growing side by side and in equal luxuriance with Arabis alpina, 
Dryas Drummondii, Erigeron hyssopifolius, Senecio discoideus, Taraxa- 
cum ceratophorum, and other plants which in their rock-habitats are 
confined primarily to areas of Group II. 
These series of habitats, the meadows, bogs, and alluvial plains, 
are alike, it will be seen, in having an extremely fine and mixed soil, 
often derived from rocks of very different kinds; and it is, apparently, 
the availability in these soils of the potassium, calcium, and often 
the magnesium, which makes it possible for plants, which in less 
favored soils are restricted to rocks high in one or another of these 
elements, to grow side by side on the bogs, meadows, and alluvial 
plains. Now, if we consider the condition of much of the northern 
hemisphere during the period when the great ice-sheet was receding 
and the arctic and subarctic plants were following in its wake, we shall 
see that there were, in America for instance, measureless stretches of 
country, from Long Island Sound northward, westward and north- 
westward and again on the western slopes of the continent, which 
were essentially identical in their character with the bogs and mead- 
ows above referred to, while there also abounded far greater deposits 
