XXV FREYCINETIA 323 



Rarotonga, according to Mr. Cheeseman, the Freycinetias are very 

 abundant on the mountains, which reach a height of 2,200 feet, the 

 plants scrambling up the trunks of trees or over rocks and fre- 

 quently rendering the forest almost impenetrable. In Tahiti, 

 Nadeaud tells us, the Freycinetias often cover in an inextricable 

 network the sides of the valleys at elevations of 2,000 to 3,300 feet, 

 extending in their vertical range from the lower levels of the island 

 to the highest inaccessible peaks which attain a maximum height 

 of about 7,300 feet. 



These plants in the Hawaiian group are common in the lower 

 woods as Hillebrand informs us, that is to say, at elevations of 

 2,000 or 3,000 feet. During my descent from Mauna Kea through 

 the Hamakua forests on the north-east side I observed that the 

 Freycinetias commenced at an altitude of 3,900 feet, and that they 

 attained their greatest development between 3,200 and 2,000 feet. 

 These plants ascended quite a thousand feet higher on these 

 mountain slopes than the Bird's Nest Fern (Asplenium Nidus), 

 which reached an altitude of 2,800 feet. In the forests on the west 

 side of Mauna Loa they were abundant at altitudes of 3,500 to 

 4,000 feet and were not noticed above 4,500 feet. On the slopes of 

 Mount Eeka in West Maui they abounded between 3,500 and 4,400 

 feet. In those localities where the forest descends to the sea, Frey- 

 cinetias occur at the coast, and on Oahu they are often found at 

 elevations under a thousand feet. 



I have but few data showing, the altitude obtained by Freycine- 

 tias in other regions, as, for instance, in their most southerly habitat in 

 New Zealand, where they give a tropical luxuriance to the forests, 

 or in their chief home in Malaya. From Schimper's observations 

 {Plant-Geography, p. 293) it would seem that they thrive in the 

 Gedeh forest of Java at elevations of about 5,000 feet. Except for 

 the lower levels, Warburg makes but few references to this subject 

 in dealing with the species. It appears to me that some very 

 interesting results might be obtained by comparing the vertical 

 range of this genus in different regions, as, for instance, in New 

 Zealand and in Borneo or in Java. We might get indications that 

 since the age of Freycinetia began the climate in tropical latitudes 

 has been getting warmer, and that the erstwhile plants of the lower 

 levels are now as a result climbing the mountain slopes. The 

 student of distribution may find here a genus that has been 

 " cornered " not only in space and time, but as regards its condi- 

 tions of existence. Since it is obvious that during a gradual in- 

 crease of temperature it would ascend the mountains and during a 



Y 2 



