322 VAUGHAN MacCAUGHEY 



standing features, common to all the forms, will be of greater 

 value and interest to fellow-workers than any attempt to further 

 multiply the descriptions of suppositious specific differences. 

 The following characters apply to the Hawaiian forms of 

 Pritchardia: 



Roots: The root system is simple and compact. The roots 

 of a mature tree have a total spread of 6 to 8 feet, although many 

 of the roots are much shorter than this. Most of the roots are 

 densely clustered immediately below the base of the tree. The 

 roots are light brown, brittle cortex and sparingly branched, 

 0.50 to 0.75 inch diameter, with a tough woody central cylinder. 

 All roots examined by the writer have been notably free from 

 disease or infestation. No economic uses are kno^\^l for the 

 root among the natives or others. 



Trunk: The loulu trunk is unarmed, and invariably un- 

 branched. Suckers or offshoots are never produced at the base, 

 although the growth of seedlings close around the base some- 

 times stunulates the soboliferous effect. The trunk is erect and 

 usually quite vertical, even in wind-swept situations. Along 

 the very windy summit ridges the erosive actions of the steep 

 slope and the positive heliotropism of the crown causes the trees 

 to lean out against the wind, rather than to yield to it. 



On the steep ravine walls the trunks are often strongly curved 

 at the base, the stem rising from this concave base. This con- 

 dition is due to the rapid erosion of the ravine-wall and the 

 effort on the part of the plant to prevent itself from sliding down 

 hill. Many woody plants on the steep slopes have this common 

 ecologic character of strongly curved bases. The base, es- 

 pecially of young palms, is sometimes swollen or bulbous, but 

 this character is variable, and its ecologic significance is not 

 known. 



The trunk of the mature palm is 4 to 40 feet in height and 6 

 to 16 inches in diameter. On wind-swept summits the average 

 height of trunk alone is 4 to 5 feet; in protected situations, as 

 in gorges and in the tall forests of Hawaii, the trunk not uncom- 

 monly rises to 25 to 35 feet, 20 feet may be taken as an average 

 height. The trunk of P. Wrightii Beccari, the Cuban Barrel or 



