34 The Botanical Gazette. (January, 
jack oak invasion was already clearly foreseen, and now they 
are over many acres so thick as to interlock their branches, 
though the trees are only ten to fifteen feet high. Even on 
foot it is at times a nuisance to penetrate through the thicker 
growths, often several acres in extent. 
The invasion seems to be from the north. At Marianna, 
and along the Appalachicola and Chipola in western Florida, 
they have not yet become a pest. West of the Flint the 
country was until lately quite free of them as a nuisance, but 
within the last several years reports have been coming in of 
the invasion of also that territory. Pines go deeper for theif 
food. Oaks seem to require more potash and more phos- 
phoric acid. Whatever the reason may be, nature, who has 
been raising pines for a long time, seems to have determined 
to quit the business, and has directed her attention to raising 
oaks. Perhaps the pines have exhausted the soil of certain 
elements, and have left others favorable to the growth of oaks 
in excess. 
An additional observation must here be recorded. Fire 1s 
set in winter to the grass in the woods to act asa natural 
manure for the coming spring. The pines catch fire more 
easily, owing to their pitch, and the cambium layer is readily 
killed by heat. Oaks under similar circumstances suffer much — 
less. A plantation house recently burnt down. Being a log” 
and board house built of the rich pitch pine of the country, 
the heat was intense for an hour at a distance of a hundred 
feet. All the pines in the vicinity were killed. Five steps 
away from the sills of the house in the direction of the draft : 
of the fire are black jack oaks, which have put out fresh 
branches all along the side of the tree away from the house 
and those within a foot of the house are putting out branches - 
from the roots. It was hoped that they were dead. Young 
fresh oaks are springing up everywhere near the burnt ground. 
Still this readier resistance to fire by oaks is only a very pat 
tial factor. On some plantations forest fires have not beet 
allowed for some years on this account, but the oaks are ste 
advancing. The worst oak in this respect is the black jack 
oak, Quercus nigra L., and it is to this oak that the tery 
weed would apply. The Turkey oak, Q. Catesbaei Michx.)¥®- 
common but not feared. . 
: Near the above mentioned house stood a pine about eight 
inches in diameter. A storm had inclined it to about fiftee? 
