IN BORNEAN FORESTS [chap, xxi 



it, is merely the result of the action of stimuli on organisms at one time 

 endowed with the faculty of modifying themselves according to 

 their environment. Admitting this, what stimulus can have pro- 

 duced the singular conformation of the leaves of this Cryptocoryne ? 

 Perhaps it was the need of enlarging the assimilating surface of 

 the leaves (the plant living in shady places) without increasing too 

 much the resistance to the water current, which might have torn it. 

 Or was it due to the current itself exercising a continuous 

 tension on the surface of the leaves in the spaces between the 

 longitudinal and the transverse ribs, and distending the tissues 

 in these parts, as the wind would a sail. Or have both the above 

 mentioned causes contributed to render hereditary a character which 

 was at first accidental, but of daily occurrence ? There are some 

 plants in which the tension of water against the leaf surface has 

 acted more energetically, lacerating the least protected places 

 so as to produce complete perforations. This is the case with 

 some of the Uvirandras. 



The above-mentioned Cryptocoryne, the cause of this digression, 

 was then in blossom, but the inflorescences were submerged and all 

 closed. Probably they only expand when the waters are very low, 

 or else the plant is one of those termed by botanists cleistogamous, 

 i.e. producing flowers which never open, not even when fecundation 

 is taking place. 



I searched most carefully on the rocks, both submerged and 

 awash, for Podostomaceae, as such places looked likely for these 

 plants, but I found none. The absence of members of this family 

 through the entire Malay Archipelago excepting Java is singular, for 

 several are found in Ceylon, whose flora offers so many affinities with 

 that of Malaysia. All the rocks we had seen so far were sandstone. 



We camped for the night on a projecting tongue of land which 

 lies at the confluence of the Mintei and the Entabei. On the bank, 

 exactly at the point where the two rivers meet, rose a most majestic 

 tapang {Abauria excelsa), one of the finest specimens of this gigantic 

 tree. I had never been able to ascertain the height of these giants 

 on account of their surroundings. But here was an excellent 

 opportunity for taking a measurement, for the tongue of land was 

 perfectly level and flat, and gave me the means of measuring a base. 

 With this datum, a very simple trigonometrical operation enabled 

 me to determine the height of the tree, which proved to be 230 feet 

 from the ground to the top of its immense crown of foliage. 1 Six 



1 I am of opinion that the heights of 450 feet and more attributed to some 

 Australian trees {Eucalyptus) are unreliable. [Mr. W. Ferguson. Inspector of 

 State Forests, measured a fallen Eucalyptus on the Watts River which by the 

 tape was 435 ft. from base to a point where it was fractured. Here its 

 diameter was 36 inches. "Before it fell." he writes, "it must have been 

 more than 500 feet high." (v. A. Trollope's Australia and New Zealand, 

 vol. 1, appendix iv.) — Ed.] 



330 



