408 THE ACORNS AND THEIR GERMINATION. 
II. VEGETATION ALONG THE LAKES. 
From THE TRANSACTIONS OF THE St. Louis ACADEMY OF ScrIENCE, VoL. IV. 1880, ProcEEDINGs. [Read in 1878.] 
THE country is partly flat, partly rolling, and is covered in many places with dense woods, [xx] 
mostly of coniferous or of deciduous soft-wood trees. Among them the “gray-oak of Canada” 
occurs, described by Michaux as Quereus borealis, or Y. ambigua, our most northern oak, found from 
Lake Superior to Lower Canada and to Nova Scotia. Its acorns and leaves cannot be distinguished 
from those of our red-oak, Q. rubra, L., of which it is without doubt a northern variety with paler bark 
and tougher wood. It grows to be a large tree of over two feet in diameter, and its wood is highly 
esteemed in those regions. I cannot make much of the figure of the acorn of Q. ambigua in 
Michaux’s Sylva; it does not resemble any form of gray-oak acorns I have seen. Can it belong to 
the following ? 
The other oak of the shores of Lake Superior is a kind of black-oak, a smaller and, up there, 
much rarer tree, but which becomes much more common farther south, on dry land in Minnesota and 
Wisconsin, and seems to extend eastwardly to the New England States. Farther south it gives way 
to the ordinary black-oak (Q. tinctoria ! Q. coccinea ?) which, though very variable in foliage, is always 
characterized by the large, thin, somewhat squarrose-tipped cup-scales: the black-oak of the Middle 
States. In Northern Illinois both are found. The northern black-oak has a very rough black bark ; 
leaves coarsely, or often very finely lobed (as to resemble the foliage of Q. palustris) ; a turbinate cup 
with small, appressed, and more or less tumid scales, so that the cup appears tuberculated almost like 
that of a white-oak. The most common white-oak of Minnesota is Q. macrocarpa, popularly known 
under the name of burr-oak. 
A few plants otherwise peculiar to the Atlantic shores also occur along the northern lakes, 
which is explained on the hypothesis that these shores were once sea-coasts. 
Til. THE ACORNS AND THEIR GERMINATION. 
From THE TRANSACTIONS OF THE ACADEMY OF SCIENCE OF Sr. Louis, VoL. IV. 1880. 
THE structure of the acorns and the germination of the oaks seemed to be so well [190 (1)] 
known, that I did not pay much further attention to it until my interest was excited by 
the information that the germinating live-oak developed little tubers, well known to the negro 
children, and greedily eaten by them. The notes and the specimens obtained from my South 
Carolina correspondents, Messrs. H. W. Ravenel, W. St. J. Mazyck (who was the first to notice this), 
and Dr. J. H. Mellichamp, enabled me to examine the germinating live-oak and to compare it with 
other oaks in this condition. I now studied the acorns, as many mature ones as I could find in my 
collection, and the oak seedlings which I had, as well as other seedling trees, carefully collected 
whenever I could obtain them. The following are the results. 
In the tip of each acorn we distinguish, imbedded between the two large fleshy cotyledons, 
first, the little caulicle, and then at its upper end (toward the centre of the acorn) the two stalks or 
petioles of these cotyledons; between these the plumule is visible, more or less developed, usually 
only a truncate or slightly notched or emarginate knob. These parts together are in the different 
species and in different sized acorns usually from one to three lines long and one-half to one line in 
diameter; in very small acorns sometimes smaller. 
