IV.—The Ferns of Mount Penrissen. —By Cecil 
J. Brooks. 
The following list of ferns collected on Mount 
Penrissen during the month of April 1910 makes no claim 
to completion, indeed the short period at the writer’s 
disposal was sufficient only for him to follow one trail to 
the summit and return by the same route; to make a 
comprehensive collection of the ferns of this large area 
would entail a very prolonged residence on the mountain. 
The large number of new species* discovered shows 
that this somewhat isolated group of mountains is 
botaniqally in its fern flora as interesting as its fauna has 
proved to be ; and it appears just to conclude from this 
small collection that the ferns of the Penrissen group are 
not so closely connected with those of the other well- 
known mountains of Sarawak proper—Mounts Matangg 
Santubong, Poe and the Bungo Range—as the ferns of 
those mountains are connected with one another. 
According to the most recent determination t Penris¬ 
sen has an elevation of 4100 feet; it is the highest of 
three peaks, Mounts Serum and Prang being the names 
of the other two; it is situated at the source of the— 
so-called—left-hand branch of the Sarawak river, within 
fairly easv access of Kuching and distant from the sea 
about 60 miles. Several naturalists have visited it, 
including Dr. G. D. Haviland, who, I believe, devoted no 
special attention to the fern flora. 
In considering the local distribution of these ferns 
the conditions are similar to those existing on all moun¬ 
tains in Sarawak; where the foot-hills are covered with 
old jungle, an extremely humid atmosphere is always 
maintained and ferns are numerous; above, for an eleva¬ 
tion of 1000 to 2000 feet, where the atmosphere is 
comparatively dry and the trunks develop to their greatest 
proportions, thus creating a gloom, the}' become scarce 
* In a collection of five species of Selaginelias determined by 
Professor Hieronymus four proved to be new to science. 
f Sarawak Gazette , January, 1910, p. 5, “Mount Penrissen,” by 
J. C. Moulton. 
Sar. Mus. Journ., No. 2, 1912. 
