661 
question to determine the original color of the bark. A number of 
gray Cladomia and Usnea-like lichens are found on the branches of the 
trees growing at higher altitudes, intermingled with the greener mosses 
and liverworts. ‘These may be seen hanging in festoons or as upright, 
fruticose forms. However, in this situation the lichen vegetation is 
comparatively insignificant. ‘The orchid epiphytes, on the other hand, 
are very rich in species and some of the latter are represented by many 
individuals. Varied forms are exhibited. The most common one en- 
countered above the 1,000-meter line is the grass-like Acoridium tenellum 
(see Pl. XXXVI) and other species of Acoridium simulate the latter 
but not so successfully. Species having exceedingly fleshy leaves are 
very abundant, some forms with and some without their leaf bases 
swollen into bulbs; others have creeping rootstalks embedded in the other 
epiphytic vegetation. When this is the case, the velamen may be poorly 
developed or be wanting altogether. Most humble is the small Taenio- 
phyllum obtusum, with no leaves at all but with roots which act as 
photosynthetic organs. In this respect the arrangement of its chloro- 
phyll and protective (velamen) tissue is exactly like that in the fruticose 
lichens, excepting that the side of the root next the substratum has no 
chlorophyll. Some idea of the richness of the orchids in species can be 
given by the following list: Corysanthes merrilli, Coelogyne  sparsa, 
Pholidata imbricata, Platyclinis glumacea, P. latifolia, Acoridium tenel- 
lum, A. whitfordii, Cestichis philippinensis, C. merrilli, C. compressa, 
Ceratostylis philippinensis, Dendrobium macraei, Eria graciliscaposa, 
Phreatia luzonienses, Bulbophyllum bataanensis, B. cuneatum, B. dasy- 
petalum, B. lasioglossum, B. whitfordii, and a large number of species 
not yet determined. (See Pls. XXXVII and XXXVIII.) The fact 
that, so far as the ridge is concerned, there is scarcely a full-grown tree 
to be found above the altitude of 1,000 meters which has not twenty or 
more specimens on it, will show the abundance of individuals. 
The second group of epiphytes is represented by mosses, leafy liver- 
worts, and the so-called “filmy” ferns (Trichomanes and Hymeno- 
phyllum). All of these are plants having very delicate, mesophytic 
leaves which, because of their texture, have the capacity of directly ab- 
sorbing moisture, and which, during the hotter and drier parts of the 
day, lose water to such an extent as to wither and curl up. (See 
Pl. XXXVIII.) They remain in this condition until the relative humid- 
ity of the atmosphere increases to a sufficient extent to enable them to 
recover their rigidity. These “resurrection” plants increase in abun- 
dance of species and individuals with the rise im the frequency of fog 
and relative humidity. Strictly spéaking, the plants last mentioned, 
like the orchids, can not be classed as epiphytes alone, for they may 
grow on old logs and rocks. At the base of the mountain, compara- 
tively speaking, there is a poor expression of moss, fern, and liverwort 
vegetation. Here they either occupy positions at the bases of the trees, 
