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ROBINSON. 
summit of Mount Malulud, the highest point, . being only 340 m above 
the sea. There are many ravines and small rivers. 
Until recently, practically nothing was known about its flora. On 
Dr. Warburg’s visit to the eastern coast df Luzon, he sent a collector 
to the Island, and the speoimens obtained are in the Berlin herbarium. 
One species, Ardisia pirifolia Mez, has been described from this source. 
In 1904, Mr. B. Hagger, of the Forestry Bureau, collected a few species, 
one of which is the type of Trigonachras cuspidata Radik., not sub- 
sequently obtained there or elsewhere. My stay upon Polillo began 
exactly with the month of August, 1909, and continued until the 24th 
of that month. Mr. R. C. McGregor, ornithologist of this Bureau, 
arrived about a week after my departure, and remained until November 
19, making extensive botanical collections, except at the beginning of 
his stay. Our routes were much the same. Both made headquarters 
in the town of Polillo, and explored the vicinity in many directions, both 
crossed by the same trail to Burdeos, one thereafter working to the north 
and the other to the south of that place, neither visited the extreme north 
of the island. 
The general result was disappointing. The total of the collection num- 
bers is 878, to which will be added several epiphyllous lichens, the flower- 
ing plants alone number 631. Many additional species of flowering 
plants are represented by leaves bearing epiphyllous hepatics or lichens, 
but not otherwise, as they were not found in flower or fruit during 
our stay. These are not enumerated. Frequently^ the same species was 
obtained by both collectors, but one of the most remarkable features of 
the exploration was that this did not occur more frequently. At the 
beginning of his stay, Mr. McGregor made few collections, through fear 
that he would merely duplicate the earlier work, and throughout passed 
by the commoner weeds for this reason. Then again, no two persons, 
passing over the same ground in a tropical forest, would make exactly 
identical collections. The real explanation is seasonal. August is the 
end of the dry season on Polillo, the time of change is somewhat variable, 
but occurred in the interval between the two periods. Iiow great a 
difference these causes produced is shown by the following figures : 
