\ 
NOTES ON PHILIPPINE ORCHIDS, III, 37 
have been identified as natives of the Philippines and of these over forty 
have been described since 1905. In other words the genus has^ computed 
on the basis of Smith's monograph^ been doubled since botanical explora- 
tions were begun by the Bureau of Science^ and of the species discovered 
more than half belong to the section Acoridium. Furthe]*more^ of the 
new species of orchids published in my contributions to our knowledge 
of the Philippine flora about one-third have been members of Den 
drocliilum. 
No similar result has been obtained in any other orchid group^ the 
only approach to it being that experienced in the study of the section 
Distichae of the genus Cesfichis; more species of this section being found 
in the Philippines than in all other regions combined. 
One point worthy of remark concerning Philippine genera of Or- 
chidaceae is that according to our present knowledge none are endemic. 
Attention was directed to this fact by Mr. Eolfe in his paper to which 
reference has already been made, and no exception to it has yet been 
noted. In connection with Mr. Rolfe's suggestions as to the probable 
derivation of the Philippine flora it is interestii5g to consider not only 
genera but subgenera or sections, and especially the species of Dendro- 
chiluin which belong to Acoridium and Pseudacoridmm. If the Phil- 
ippine flora is to be regarded as of comparatively recent formation by 
the introduction of species from neighboring territor}', it is intensely in- 
teresting to study such subgenera or sections as Acoridium in Dendro- 
ckihim and Distichae in Cestichis, and to contemplate the cause of the 
remarkable development they seem to have experienced. Unfortunately, 
the orchid flora of the neighboring islands, if we except Java, has not 
been sufficiently investigated to warrant any definitive conclusions, but 
what is known makes possible a fascinating comparative study wliich 
indicates that in certain Philippine orchid genera there has been un- 
usual development, or a minimum of extinction after introduction from 
regions less favorable to the species introduced. When the flora of ad- 
, jacent islands is more thorouglily studied as we may find other centers 
of distribution for Acoridium and an extension of range for species now 
believed to be endemic. But on the basis of existing records this group 
is localized in the Philippines with only a few representatives in other 
parts of the Malayan Archipelago. 
Prom a horticultural or economic viewpoint the orchid flora of the 
Philippines is of little importance. With the exception of a few species 
of Aerides, Dendrohium, Eria, PapJiiopedilum, Phalaenopm and Vanda 
there are none which may be assigned to the first rank of horticultural 
acquisitions. 
If we distribute the Philippine genera among the five tribes admitted 
by Bentham in the "Genera Plantarum," which for conciseness and ease 
of comprehension are very useful and much less confusing than Pfitzer's 
