216 The Philippine Journal of Science 1914 
explanation of the facts, or whether both contain elements of 
truth. In either case, the same species might be found in regions 
of quite dissimilar rain-distribution ; so that the contrast between 
such regions, if based on the mere presence and absence of 
species, would have to be between plants with strong preference. 
It is sufficiently assured that there are certain trees, for example, 
that grow under both sets of conditions, but much better under 
one. But it is obvious that it is • impossible for very definite 
statements to be made on this point for more than a very few 
of the forest species. 
What the theory seeks is to establish a correlation between the 
rainfall and the geographic distribution of species. In northern 
Luzon, the narrow western coastal plain is separated from the 
broad Cagayan Valley and the east coast by the whole mass of 
the Mountain Province, but the hills taper down to the north, 
and the plant evidence is that in the extreme northwest, namely 
in at least the northern part of the Province of Ilocos Norte, 
there is an extension of species found on the east coast but not 
in the more southern provinces of western Luzon. On this point 
the mosses in this herbarium furnish no evidence, for not one 
species has yet been collected in either Ilocos Norte or Ilocos 
Sur, and not many in Union. Their total is probably small. 
Nor are there many from the Batanes Islands, nor from Cagayan, 
nor Isabela, but some of these have proven of considerable 
interest. There is nothing from the east coast until just north 
of the latitude of Manila, the intervening country being to-day 
about the least accessible region in the Philippines. Then follows 
the best known portion, bryologically, of eastern Luzon, Infanta, 
Polillo, San Antonio in Laguna Province, and especially two 
of the hills of the Banajao group, Banajao proper, and the lesser 
Banajao or Lucban. It is again to be remembered, also, that 
the mosses differ from the great majority of the species of 
flowering plants, in that the latter have been collected at all 
levels, whereas the former have mostly come from high eleva- 
tions, especially the “mossy forest,” where the humidity is great, 
at all seasons and on all slopes. 
In practice, therefore, all that can be ascertained here is 
whether the mosses known from the western provinces of Ilocos 
(none), Union, Pangasinan (none), Tarlac, Pampanga, Bulacan, 
Zambales, Bataan, and Cavite seem to differ from those of In- 
fanta, Polillo, Laguna, Tayabas, Camarines, and Albay on the 
east, and whether either of these groups seems to show any 
preference for extension into the Visayan and the southern 
islands, or outside the Archipelago. Rizal Province is not a 
