222 
taken for one individual. One of these trees is a White Oak, 
the other being a Black Birch, and from seedlings on, their 
growth has been so even that neither one has gained any advan- 
tage over the other. For the space of 3 ft. 7 in. from the 
roots they have grown solidly together, so that the line of junc- 
ture isno more marked than the weather worn crevices down 
the sides of many large trees, the character of the bark serving 
as the best guide in distinguishing the trunk of one tree from 
that of the other. At the height mentioned from the ground the 
trunks part or branch, forming a Y, the oak being 4 ft. 2 in. in 
circumference, and the birch 4 ft. 5 in., while the main trunk, 
formed by both trees, measures 7 ft. 4 in. around. 
It is no uncommon matter to find cedar branches, owing to 
their unpliability, enclosed by the trunks of other trees, and some 
species often become grafted together, but the case mentioned 
seems to be interesting as a departure from these general rules, 
and also from the symmetrical outline that has been maintained. 
W. T. DAVIS. 
Index to Recent American Botanical Literature. 
Agarum Turneri.—On the Anatomy and Development of. James 
Elias Humphrey. (Proc. Amer. Acad. Arts and Sciences, 
XXli., pp. 195-204; two plates; also reprinted.) 
This investigation is the seventh contribution from the crypto- 
gamic laboratory of Harvard University, conducted under the 
direction of Dr. Farlow. Mr. Humphrey finds that the structure 
of the adult frond of this curious Alga agrees closely with that of 
Laminaria, that the frond increases in length at the union of 
stipe and lamina, and that the perforations of the latter begin 
when a length of 3 to 4 centimetres is attained, and are formed 
by the simultaneous formation of an indentation of one surface 
and the death of a corresponding portion of the other. 
Azalea nudiflora.—(Vick’s Ill. Month. Mag., ix., p. 294; colored 
figure.) 
Bacteria apparatus—Home.made.—T. J. Burrill. (Bot. Gazette, 
xi., p. 276, illustrated.) 
Biology of Timber Trees with special reference to the require- 
ments of Forestry. —B. E. Fernow. (Bot. Gazette, xi., p. 247-) 
