TROPICAL FLORAS T9 



mountain with two summits. During the ascent I was much 

 impressed by the extreme hixuriance of the forest-growth, and 

 especially of the undergrowth of ferns and herbaceous plants. 

 I was told by the gardener in charge of the nursery of 

 cinchonas and other plants, that 300 species of ferns had been 

 found on this mountain, and I think 500 orchids. I was 

 therefore anxious to learn if any figures for the plants of 

 the whole mountain could be obtained, and was advised by 

 the Director of Kew Gardens to apply to Dr. S. Koorders of 

 the Reijks Museum, Leiden. In reply to my inquiries, Dr. 

 Koorders wrote me as follows : — 



"The botanical mountain-reserve on the Gede (Pangerango) is 

 indeed very interesting and very rich, but I know other parts of 

 Java with a much larger number of phanerogams, e. g., the small 

 island of Xoesa Kambangan near Tjilatjap. On that island I 

 collected on an area of about 3 square kilometres (= 1% square 

 mile) 600 of arborescent species of phanerogams, and about 1800 

 species of not-arborescent species. This island is about — 50 m. 

 altitude (=164 feet).'' 



" On Mount Pangerango, between 5350 feet and the top, 10,000 

 feet, the number of forest-trees is about 350 species on the same 

 area, and about 1400 species of not-arborescent phanerogams." 



On reading the above, I thought at first that Dr. Koorders 

 must have made a mistake, and have meant to write 30 in- 

 stead of 3 square kilometres. So I wrote to him again ask- 

 ing for some further information, and pointing out that 

 Kambangan Island was many times larger than the area he 

 had given. To this he replied that he " only explored a small 

 part methodically," and that the number of species he gave 

 me '^ were found in that part only." ^ It thus became clear 



1 It may seem to some readers, as it did at first to myself, that it is im- 

 possible to have over two thousand species of flowering plants growing 

 naturally on about a square mile. But a little consideration will show 

 that it is by no means so extraordinary as it seems. Let us suppose that 

 the average distance apart of trees in an equatorial forest is ten yards, 

 which I think is much more than the average; then in a square mile there 

 will be 176 X 170 = 30,976 trees. But in Kambangan Island there are 600 



