MOUNTAIN MYXOMYCETES 
T. H. Macbride 
Slime moulds are such ubiquitous things that we might imagine 
all species universally distributed and the forms of one locality 
precisely those of every other, once the lists are with accuracy 
compared. This might well be the case indeed since these forms 
are manifestly sown by wind currents, their spores swept by every 
aerial movement, probably round and round the world. 
Furthermore, slime moulds, in the nature of the case, are essen- 
tially woodland things ; they affect the shade, love rotting logs 
and piles of fallen leaves, and one might expect to find them alike 
in all the forests of the continent. But such is by no means the 
situation. These curious heirs of primitive life differ in different 
forests, and vary from mountain range to mountain range, and 
up and down the meridians of the world, quite as do the higher 
plants. They respond readily to environmental change and be- 
come fixed at length in haunt and habitat. 
The variation is accordingly more marked where isolation and 
climatic differentiation are more complete. Thus there is more 
concord if we compare the forests of Maine and Washington 
than when we attempt to study together the Rocky Mountains 
and the Cascades. Maine and Washington are near the ocean ; 
the Rocky Mountains are far interior ; the mountains about Puget 
Sound are visited by abundant rains, the Rocky Mountains are 
semi-arid; stretch across the “great American desert.” 
This opens a wide subject. It is not expected here to do more 
than call attention to the problem. This we may effect by pre- 
senting briefly the slime-mould species of the two regions latest 
named, comparing particularly Colorado and the shores of Puget 
Sound. Most of the work in Colorado has been done by Pro- 
fessor E. Bethel and Professor W. C. Sturgis; I myself have been 
busy on tbe Pacific coast. For some reason, not clear to me at 
present, tbe Colorado field is remarkable for its wealth of cal- 
careous types : at least in the light of present knowledge, the 
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