130 College of Forestry 
Michauxu, Fagus americana (Ff. grandifolia) invade land 
formerly occupied by white cedar.” 
Notable Working Units in Bog Vegetation. 
The effectiveness of bog vegetation has been inferred from 
previous mention of the character and amount of peat laid 
down by it. The above caption is employed for the purpose 
of focusing attention upon two unique growth forms as 
‘working units” characteristic of bogs. These are (1) 
Sphagnum and (2) heath shrubs. 
(1) The characteristics and role of Sphagnum. 
Botanically, Sphagnum is one of the genera of mosses, the 
only genus of its special group Spagnales. There are perhaps 
250 species all told of which perhaps 30 to 40 species * may 
occur in New York. Popularly it is simply peat moss which, 
considered from our present viewpoint, has peculiarities of 
structure and habits of growth which give it unique qualities 
as to taking up and holding water. Hence its use by florists 
and nurserymen. Laled peat moss is a standard article of 
commerce in this connection. Fig. 18 shows a view of an 
Adirondack bog from which peat moss is taken for packing 
young transplants from the State nursery at Lake Clear. This 
view will also indicate the character of mat which Sphagnum 
builds up. These mosses may in fact be the chief — some- 
times practically the sole agents in peat formation. As 
pointed out in describing a bog near Phoenix, the Sphagnum 
mat may consist of recognizable Sphagnum plants to a depth 
of a foot or so, but below this it is more or less disintegrated. 
It is often — I believe generally — associated with sedges in 
forming the zone of floating Sphagnum-sedge mat which car- 
ries forward the invasion of land vegetation out over the open 
water zone (recall the case of Devil’s Dye-tub). In the 
Sphagnum-heath shrub mat, Sphagnum makes an aggressive 
upward growth among the shrubs, the two together forming 
small mounds in this part of the bog. Statements as to 
1 The number of species of Sphagnum listed from Connecticut is 31. 
