204 BOTANICAL GAZETTE [MARCH 
allowed to run for 50 days. Up to the end of that time the pinnae 
and the 1 cm. pieces were normal in appearance in all three species, 
excepting that in 7. capillaceum the cells had become disorganized 
for two or three rows back from the cut ends. The pieces 3 mm. 
long failed to maintain normal condition. 
These tests indicate that separate leaves are capable of surviving 
and maintaining normal appearance, and that portions of leaves 
are also capable of doing so provided they are not so small that the 
disorganization which takes place at the cut edges leaves only two 
or three rows of cells along the center that might be expected to 
" survive. So far as concerns the vegetative functioning of the plant, 
the leaves are quite independent.of each other, and, when the leaf 
is completely wet, the individual cells are as independent as are 
those of a colonial alga. 
The water by which the leaves of the Hymenophyllaceae are 
bathed in nature is usually rain water that has either fallen directly 
upon them or has dripped from foliage that has already been washed 
clean by frequent rainfall, and is therefore not capable of carrymg 
any mineral salts to the plant. The water which is available to the 
roots, however, has usually been for some time in contact with 
epiphytic colonies of moss and flowering plants, and with the rotting 
leaves and bark always to be found beneath clumps of epiphytes, 
and I assume that it is rather rich in salts, including nitrates. The 
water which drips down over the leaves of pendant species is the 
same as that available to the roots of other species. 
Plasmolysis with NaCl gave the following values for the osmotic 
strength of the sap of a few of the common species: Trichomanes 
rigidum, T. radicans, T. crispum, and Hymenophyllum sericeum; 
0.4283N; Hymenophyllum asplenioides and H. elegantissimum, 
0.514N. 
THE CHLOROPLASTS.—The chloroplasts of the filmy ferns are 
spherical and somewhat smaller than in most other groups of ferns- 
In all the Jamaican species they lie normally in a single densely 
packed layer next the two outside walls of the leaf cells (fg: 7): 
There is rarely a difference in their abundance on the two sides of 
the leaf. 
A paleness in the coloration of the leaves of Trichomanes radt- 
