ORCHIDACEAE 
botanical activities of the Bureau of Science and of private col- 
lectors have been pretty constant during the last fifteen years, 
there are numerous orchids that are represented in herbaria by 
the specimens of a single collection. This is in part accounted for 
by the tendency of orchids to occur sporadically, but is largely due 
to the fact that there are regions in which botanical exploration 
has been limited to a single effort or to a cursory examination. 
From time to time the relationship of the Philippine flora to 
that of the other Malayan islands has been discussed. In the fifth 
fascicle of this work I referred to the subject very briefly and 
indicated that the alliance between the orchid floras of the Phil- 
ippines, Celebes and Java was somewhat close. Recently I have 
had an opportunity to study the Bornean collections of Chaplain 
Joseph Clemens. Although these were confined to Mount Kina- 
balu in British North Borneo, they tend to show that the rela- 
tionship between the orchid flora of the Philippines and that of 
Borneo is not so close as geographical considerations would seem 
to indicate. In my studies I was deeply impressed by the absence 
of species from the Bornean collections that are common to the 
higher altitudes of the Philippines. Under Dendrochilum in the 
enumeration of the orchids of Mount Kinabalu I have discussed 
this point at some length, and the remarks made therein are 
applicable in general to the other Bornean orchid genera. 
Until we know more about the floras of Borneo and Sumatra it 
will be impossible to arrive at satisfactory conclusions regarding 
the distribution of orchids in the Malayan tropics. It is becoming 
clear that endemism is more pronounced than we had believed, 
and that many of those species now supposed to extend over a 
wide range may prove to be made up of several different species, 
each one restricted to a well-defined area. Of course there are 
dominant species, such for example, as Spiranthes sinensis (Pers.) 
