2go 
INTRODUCTION TO 
Sixth: Collections made in 1916 on a trip to Mt. 
Kinabalu by Mrs. Clemens and Mr. Topping, which 
together constitute very much the largest collection of 
Bornean ferns which has ever left the island at one time. 
Mr. Topping is an enthusiastic fern amateur of long 
standing, and Mrs. Clemens is an unusually keen collector 
of ferns, as well as of other plants. Their collections have 
revealed for the first time the presence of a considerable 
fern flora at and above the tree-line, the absence of which 
has been a puzzle to me for years. 
The enumeration of the collections which have been 
in my hands, and the use of these collections, with the 
literature on the subject, as the material basis for the 
preparation of a general paper on the ferns of Borneo, 
must not be construed as even an implication that there 
have not been other and very important collections of 
Bornean ferns. Authors as early as Mettenius had the 
use of collections of considerable size made chiefly by 
Dutch botanists. Various visitors to Mt. Kinabalu have 
collected extensively there, and to some extent elsewhere 
in the Island; among these, Burbidge and Haviland 
should be particularly mentioned. And the years of work 
of Bishop Hose must receive permanent and most 
emphatic appreciation. The papers, chiefly by Baker, 
dealing with these various collections, have contributed 
to our present knowledge of the ferns of Borneo in a 
manner which is most evident if one notes the number of 
species which Baker has described there. A complete 
bibliography of Bornean botany, including all papers 
known to me on Bornean ferns up to the date of its 
publication, prepared by Mr. E. D. Merrill, is found in 
this journal, Vol. II, No. 6, 1915 - 
In the arrangement of the genera of the Polypodiaceae 
and in fixing the limits which should be recognized for 
