A STUDY OF TILLANDSIA USNEOIDES. 
FREDERICK H, BILLINGS. 
(WITH ONE FIGURE AND PLATES VIII-X1) 
Tillandsia usneoides, popularly called “long moss,” “black 
moss,” or “Spanish moss,” is the most widely distributed representa- 
tive of the tropical and subtropical family Bromeliaceae. Accord- 
ing to SCHIMPER (1) it extends from southern Virginia, its northern 
limit, as far southward as the Argentine Confederation. It forms 
everywhere a conspicuous and characteristic object of the landscape, 
its long gray festoons adorning not only trees of the virgin forest but 
many cultivated ones as well. Although the beauty of the landscape 
is enhanced by its presence, its growth upon ornamental trees is 
regarded often with apprehension, a common impression being that it 
lives parasitically. A most casual examination, however, will reveal 
the fact that the moss is in no way connected with the tree, but merely 
wraps its dead, wiry stems loosely around the twigs in order to support 
itself. Old festoons which have hung in the same place for years 
occasionally show a connection with the bark, the annual growths of 
the limb finally enclosing some of the decorticated moss stems; much 
in the same way that an old horseshoe hung astride a branch and left 
unmoved for a long time will be partially enclosed. 
An indirect cause of the popular belief in the parasitism of Til- 
landsia is its preference for sunny exposures. This habit would tend 
to keep it from trees having a dense shade. In dark forests it hangs 
suspended from the higher limbs of tall trees, especially those that 
are dead. Many a cultivated tree when in perfectly healthy condition 
possesses too dense foliage to serve as a host for Tillandsia, but if for 
some reason the supply of leaves should be reduced, the light condi- 
tions might be such as to make the presence of the epiphyte possible. 
Should it make its appearance, the owner of the tree would be very 
apt to regard the moss as the cause rather than the result of the reduced 
foliage. A proof of the true epiphytism of the plant is its long- 
continued and vigorous growth upon decorticated limbs of dead trees. 
Near Baton Rouge are many such trees, killed by girdling long ago, 
1904] - 99 
