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As the iron compounds penetrate the moss tissue, a hard porous tufa is formed 
which becomes a part of the accumulation of bog iron ore about these springs. 
Together with other species of plants this moss may aid in building up a mound 
so high as to make it necessary for the water of the spring to find a new and 
lower place of escape. 
Very much the same situation occurs at Turkey Run, Indiana, where Crato- 
neuron filicinum (L.)Roth. is found as a tufa former in calcareous springs. 
Near the head of Lake Michigan in northern Indiana are many ponds, 
forming a series extending southward from the present beach. These are long, 
narrow lagoons cut off originally from the lake proper by barrier beaches which 
were built up near the lake margin by water currents, and which lie nearly parallel 
to the shore line. The lagoons vary in depth and size as well as in ecological 
age, while the ridges or old sand bars are now, in many cases, forested with oak. 
In some of the deeper lagoons are floating islands which seem to have had 
their origin in a surface mat formed over the water as in the case of quaking bogs. 
Portions of the mat have here broken loose from the shore, and now form small 
islands floating without attachment to bottom or margin. 
One of the chief agents in the formation of the mat, and still found in great 
abundance on the islands, is Campylium stellatum (Schreb.) Bryhn. The same 
species of moss has been found along the margin of the smaller lagoons, in the 
shallow pine “pannes” among the sand dunes near Miller, Indiana, and on 
the surface mat of the quaking bog at Mineral Springs, Indiana. This species 
does not form a tufa, as in the former case, but takes a large part in filling up 
bodies of water by growth upon the ground either submerged or emerging, and 
by aiding in the formation of a surface mat. 
The pannes are low depressinns arming the dunes frequently with the sur- 
face little, if at all, above the lake level. Water sweeps through the sand from 
the lake or from streams during times of high water-level. It may rise only 
to the su.face or may, in some instances, reach a depth of a foot or more. 
Around the margin of the deeper ponds may be found cottonwoods or willows, 
or if the panne is of an older ecological succession, the edge may be bordered 
with pines. Here Campylium stellatum is often abundant either submerged or 
above the surface at the margin and many may be found growing even among 
the pines. 
Milwaukee-Downer College, 
Milwaukee, Wise. 
A HERBARIUM NOTE 
Edward B. Chamberlain 
For several years it has been impossible for me to keep the larger portion 
of my herbarium in New York, owing to lack of room. In order to have for 
comparison a series of authentic specimens, I have mounted in the manner 
described below a number of sets of exsiccati, and it may be that the method 
