474 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1911. 
Jenman cites Alsophila armata and Cyathea furfuracea in Jamaica as 
occasionally branched and having two or more crowns, and Alsophila 
aspera as having produced in one instance several stems from a 
single base. The peculiar Dicksonia Berteroana of Juan Fernandez 
is sald to divide at the base, having branches up to 18 feet long and 
‘“‘thick as one’s leg.’ A notable instance also is that of a New 
Zealand species, Hemitelia Smithu, as described and figured by 
Buchanon, in which a specimen 16 feet high had no less than 16 
branches. In Alsophila quadripinnata, previously mentioned, the 
branching is at or near the ground, as in Dicksonia Berteroana. 
Christ has also mentioned on Werckle’s authority a remarkable 
example of adventitious growth in a Costa Rican tree fern (Cyathea 
sp.) which is worthy of further investigation. In this plant buds are 
said to have been borne in all the axils of the leaves, their position 
therefore being at the upper side of the leaf scar after the fronds were 
fallen from the trunk. Although a comparatively small number of 
these developed, yet the stem was several times branched at a height 
of 5 feet, and the larger of the branches formed a beautiful crown of 
more than 25 branches. 
In a large number of Cyatheacez having treelike stems one of the 
most conspicuous features is the development of adventitious roots, 
which encircle the older portions of the trunk in a hard, wiry, closely 
interwoven mass, very much like bark. These roots are commonly 
produced in great abundance, often wholly obscuring the original 
proportions of the stem, which may, indeed, appear in cross section 
merely as a core, measuring but one-fourth to one-half the total 
diameter. Toward the bottom of the trunk they are especially 
abundant, as might be expected, and frequently occur in such quan- 
tity as to form a massive conical base, which undoubtedly serves to 
give stability to the lofty stem, as in Cyathea suprastrigosa (C. con- 
spicua), a species inhabiting the upper slopes of several Costa Rican 
volcanoes, whose huge base is said to measure a full 5 feet in diame- 
ter. There can be little doubt also that the formation of the dense 
indurated covering of the lower and middle portions of the trunk 
proper gives great strength and rigidity to the otherwise slender 
stem,-which better enable it to support the weight of the upper 
part, including the great spreading crown of succulent leaves. The 
production of these aerial roots is apparently continuous, the diame- 
ter of the complete ‘‘trunk” (stem and aerial roots combined) thus 
roughly keeping pace with the elongation of the trunk. 
Tree fern trunks of this sort are the favorite home of many filmy 
ferns (Hymenophyllacex), a few of which, like Trichomanes capil- 
laceum (T. trichoideum), are not often found in other places. The 
sight of a huge fern trunk, its rough surface clothed on all sides in a 
lacelike mantle of this most delicate of all ferns, each of their hair- 
