4776 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1911. 
According to Christ Alsophila elongata is thus utilized in Colombia, 
and the trunks of Dicksonia Sellowiana in Brazil by planters in 
making inclosures for their farms. In Colombia Mr. Frank M. 
Chapman has observed the occasional use of tree fern trunks “‘pos- 
sibly 14 feet in height above the surface of the ground”’ as telegraph 
poles, although as a rule bamboos are ordinarily there used for this 
purpose. 
Still another use is made in Hawaii of Cibotium trunks, which, as 
mentioned above, there grow to such enormous proportions. Mr. 
Henshaw states that it is a common practice to make trails, 1 to 5 
miles long, leading through the woods to the coffee plantations in 
the mountains, entirely out of Cibotium trunks, either whole or 
split in halves. He adds that the coarse thick covering of adven- 
titious roots provides a springy, well-drained surface for walking, and 
that trails thus constructed, by the convenient use of these trunks 
as a rough and nearly indestructible planking, afford ready access 
to plantations through wet forests which otherwise would prove 
almost impassable. 
THE LEAVES. 
Considerable attention has been devoted thus far to a consideration 
of the rhizome, which has been found to assume different forms of 
growth and to vary greatly in nearly all respects. A similar diversity 
is exhibited also by the leaves or, as they are commonly called, the 
fronds. Of the two tribes between which the North American species 
are divided, the Cyathee and Dicksoniezw, the former presents not 
only a far greater variety in vegetative form, but also a much higher 
differentiation of special structures. It will, therefore, be desirable 
to consider the two tribes separately, though it is impossible in the 
present paper to do more than indicate briefly some of the more typical 
structural and vegetative features of each. 
LEAVES OF THE CYATHE. 
The leaves of the Cyathex vary in length from 1 foot to 15 feet, the 
two examples previously cited being Alsophila Kuhn and Cyathea 
Brunei, respectively. In position they have been mentioned as arch- 
ing in a semierect crown, spreading, or even drooping, their attach- 
ment (in arborescent species) varying from nearly vertical to hori- 
zontal, and thus determining, in connection with the rate of growth, 
the shape, size, and relative position of the leaf scars. In addition 
to the general shape and cutting of the leaf blades there remain now 
to be noticed especially the thornlike armature of the stipes (leaf 
stalks) and rachises (primary and secondary midribs of the blades), 
the covering of the growing crown, and the production of minute scales 
and hairs of many different kinds not only upon the vascular parts of 
