CONCENTRATION OF TISSUE FLUIDS OF EPIPHYTES 
record it as occurring ''on trees, rocks, and dry banks," gives on the 
average A = 0.51, P = 6.1 in the Leeward ravines and A = 0.55, 
P = 6.6 in the ruinate. Prescottia stachyoides from the windward 
ravines and slopes gave an average depression of A — 0.52, or an 
average concentration in atmospheres of P = 6.3. 
All of these values are distinctly, and in many cases very much, 
greater than those obtained from the individual species of epiphytic 
Orchidaceae. 
For comparison with the epiphytic Peperomia we have only 
Peperomia stellata, which we collected in Jamaica only as a terrestrial 
herb. It gave the following values: 
These values are slightly higher than the averages for any of the 
epiphytic species from the rain forest. 
As far as I am aware, the only determination of osmotic concen- 
tration of the tissue fluids of any bromeliad hitherto made is that for 
Bromelia Pinguim, which Mr. Lawrence and I (1917&) found growing 
as a terrestrial plant in the Jamaican coastal deserts. This gave 
A = 0.63, P = 7.6. This is a value higher than any of those recorded 
in this paper with the exception of those for Dendropogon usneoides. 
It is, however, extremely low for such a habitat as the Jamaican 
Coastal Deserts. 
With regard to two species which Mr. Lawrence and I treated with 
the terrestrial vegetation but which others have observed growing as 
air plants, the following points may be noted. 
The woody-stemmed Blakea trinervia, which may be rooted in the 
soil or, according to Shreve, grown as an epiphyte, has a concentration 
measured by A = 0.58, P = 6.9, as compared with the general average 
of A = 0.81, P = 9.7 for the ligneous species of the windward habitats 
in which it occurs. 
Tradescantia muUiflora, which we included with terrestrial vege- 
tation in our earlier paper, but which may also occur as an epiphyte, 
gave in a single determination A = 0.39, P = 4.7. This is far lower 
than the general averages of A = 6.3, P = 7.6 for the herbs of the 
Leeward ravines. 
Leeward ravines, A 
Ridge Forest, A 
Leeward habitats, A 
043. P = 5-2 
045, P = 54 
0.42, P = 5.1 
