LACTARIAE OF THE UNITED STATES 7 
tribution of the genus in the West is explained by the fact that in 
some of the western states no collections of fleshy fungi have been 
made. But enough has been done to indicate that some species will 
be found in any state, wherever the forest conditions are favorable. 
Within the limits of the United States, latitude seems to affect 
the distribution of Lactariae chiefly іп so far as it controls the char- 
acter of the forest. Lactaria Indigo Schw., which grows in pine 
woods, has been found from Florida to the Adirondack region. 
Lactaria deliciosa, L. subpurpurea, апа Г. atroviridis have a like 
distribution. Ош of thirty-one species which I found in North 
Carolina, twenty-three occur as far north as Vermont, one has a 
northern distribution in Europe, Z. Ресей has been found as far 
north as Long Island, and six others have not been described 
before. 2. salmonea Peck, from Alabama, and L. suġvellerea Peck, 
have not as yet been found north of North Carolina. 
Elevation also influences the distribution of species in propor- 
tion as it produces different ecological conditions. At 500 meters 
in Vermont, where the oaks are practically lacking, Г. piperata 
(L.) Fr. and ZL. lactifiua L. rarely occur, while at 1,000 to 1,200 
meters in North Carolina, where oaks and chestnuts form about 
70 per cent. of the forest, these species are very abundant, but 
they disappear as one approaches the spruce line. At this altitude 
one begins to notice the combined effects of latitude and elevation. 
The condition of spruce forests in the southern states differs from 
that in the North. Тһе greater elevation of the dividing line 
between oaks and spruces causes a greater daily range of temper- 
ature and the nights may be too cold for certain spruce-loving 
species. Оп this account it is probable that a species like Z. resima 
Fr. will be found to be limited to northern forests. In the south- 
ern mountains below the spruce line, on account of the great 
humidity there will be not only a profusion of fungi but one might 
expect to find certain species which would thrive only under such 
moisture conditions. It is also possible that the unglaciated con- 
dition of the southern states may account for the occurrence of 
some species which seem to be limited to that region. This can 
not be stated with certainty until further field work proves that 
such species as L. speciosa, L. agglutinata, L. salmonea, etc., are 
not found north of the glacial line. Not enough is known about 
