204 BOTANICAL GAZETTE [MARCH 
elongation, keeping pace in this way with the building up of the 
moss. Carex limosa itself survives for a considerable time. Stalks 
of this species apparently growing on the sphagnum can always be 
traced down to the stratum beneath, and the buried portions are 
found to be covered with dead remnants of leaves (fig. 40). Men- 
yanthes manages to persist for a time in a similar way. Sar- 
racenia, which as a rule precedes the sphagnum, makes use of the 
same method in an endeavor to hold its own, but is less successful 
Fic. 41.—Zonal arrangement of bog shrubs: Andromeda in the foreground, mainly 
upon the sedge mat; oss a ground at the right) mainly upon a 
mound of sphagnum; Raspberry Is 
and is soon buried. Certain of the bog shrubs belong to the same 
class. Chamaedaphne, Andromeda, and Salix pedicellaris usually 
precede the sphagnum. When the moss starts its growth in the 
vicinity of these plants it builds up rapidly around their stems, 
forming the hummocks that are so characteristic of sphagnum bogs. 
Of the three shrubs, Chamaedaphne has the greatest power of hold- 
ing its own against the smothering tendency of the moss (fig. 40); 
the willow is next; while Andromeda soon succumbs. 
The two important bog shrubs, Andromeda and Chamaedaphne, 
are zonally arranged (fig. 41). Andromeda grows freely on the sedge 
mat, especially in the wetter parts, is. most abundant just at the 
