Vegetation of the Engadine. 365 
Arolla pine, on older and somewhat acidic soils, consists of heathy 
undershrubs ; and that of the forest of the Engadine pine, on wetter 
soils, contains much Vactinium vitis-idcea. 1 
The scrub “ vegetation type ” is divided into two “ formation 
groups,” (1) the tall scrub and (2) the low scrub. The tall scrub 
shows two formations, (1) the scrub of green alder (Alims viridis) 
and (2) the scrub of mountain pine ( Finns montana). The green 
alder scrub occurs on the mountain slopes, prefers situations where 
there is a flow of water, and usually follows the streams. The soil 
is thus not only well-watered, but the water is well-aerated. The 
scrub is static; and, seen from tbe outside, it appears as a dense, 
dark green mass of high bushes with few or no shrubby or arboreal 
associates. The mountain pine scrub also occurs on the mountain 
slopes, but in drier situations. In the Pyrenees, it may be added, 
Pinus montana forms high forest; whilst in Austria, it is often a low 
gnarled shrub. 
Of the low scrub (Kleinstraucher) “ formation group,” 
Dr. Riibel recognises two “ formations,” (1) the dwarf shrub 
(Zwerggestrauch) vegetation and (2) the espalier shrub (Spalier- 
gestrauch) vegetation. The former is perhaps the most widespread 
of the plant communities of the Engadine, and is consequently very 
prominent on the vegetation map. It often covers the ground in 
the woods of Arolla pines, and sometimes in the green alder scrub 
and tbe scrub of mountain pine. It ascends higher than the 
present tree limit or dwarf-tree limit; and some Swiss plant 
geographers look upon its upper limit as indicating the former 
upper limit of trees. In this formation, Dr. Riibel distinguishes 
the following associations:—Rhododendretum ferruginei, 2 Vacci- 
nietum myrtilli; Callunetum vulgaris ; Calamagrostidetum villosae; 
Juniperetum nanse ; Arctostaphyletum uvae-ursi. A community of 
Vaccinium vitis-idcea is placed as a sub-association ( Nebentypus ) of 
the Vaccinietum myrtilli. The soil of this formation is shallow and 
acidic. 
The espalier shrub “formation” of the Engadine is a low 
growing, light demanding, humus (acidic) demanding community 
which alternates with the dwarf-shrub associations. Dr. Riibel 
distinguishes an association of Azalea procumbens (with a sub¬ 
association of Vaccinium nliginosum), and an association of Dryas 
octopetala. Dr. Riibel would have liked to have found another 
term to designate this “ formation,” as Vactinium nliginosum is a 
dwarf shrub and not an espalier shrub; but he has been unable to 
find a better word, and so continues to use this one known 
from Professor Schroter’s works. The formation receives no 
special colour on the vegetation map. 
' I have not noted any allusion to birch woods by Dr. Rubel; but there 
is a small community of Betula pubesceus in the Val Roseg. During my short 
stay in the district, I only saw two plants of B. alba (B. verrucosa) : these were 
near Pontresina. 
It may be of interest to add that the following trees are dominant in types 
of forest in other parts of Switzerland:— Quercus pubesceus; Q. pubesceus and 
Ostrya carpinifolia; Castanea saliva; Fagus sylvatica; Abies alba (A. peetinata) ; Picea 
excelsa (2). 
2 Rhododendretum hirsuti occurs on calcareous soils ; but such soils are 
rather of limited extent in the Engadine, 
