The Polynesian Species of Myoporum^ 
Grady L. Webster^ 
INTRODUCTION 
This revision was originally begun as an 
analysis of the notoriously polymorphic 
species Myoporum sandwicense of the Hawaiian 
Islands. After a considerable amount of work 
had been done, however, it was found that 
the forms of Myoporum from southern Poly- 
nesia were very similar. Because of the close- 
ness of relationship, it seemed both more 
practical and more worth while to treat all of 
the Polynesian species together. 
In the Hawaiian Islands, Myoporum sandwi- 
cense is an evergreen shrub or tree which 
grows mostly in dry forests on leeward slopes 
from sea level to an altitude of 10,000 feet. 
Its plasticity in habit is remarkable, as it may 
become a tree 15 meters high in the dry 
forests (Rock, 1913: 427) or a creeping, 
fleshy, prostrate shrub on the beaches and low 
rocky islets. More rarely it may even invade 
the rain-forest, as in Waikolu Valley on 
Molokai. 
The Hawaiians used the species, which they 
called naio, for timber in building houses 
(Brigham, 1908: 83). Apparently it was not 
cultivated, as it is in Rarotonga (Wilder, 
1931: 100), for the perfume of the flowers. 
There are references (Bennett, 1832: 257; 
Hooker and Arnott, 1841: 93) concerning the 
attempts of traders of the 1820’s to substitute 
naio wood for sandalwood in the Chinese 
iPart of a thesis submitted in partial fulfilment of re- 
quirements for the degree of Master of Arts in Botany 
at the University of Texas. Manuscript received Sep- 
tember 22 , 1949. 
^Former graduate assistant in Botany, University of 
Hawaii, and Teaching Assistant in Biology, University 
of Texas; now at the Herbarium, University Museum, 
University of Michigan. 
trade, but neither then nor since has the naio 
attained any real commercial value. Brown 
(1935: 279) reports that on the island of Rapa 
(in southern Polynesia) naio wood is used 
for building canoes and houses. 
The real value of Myoporum to the Hawaiian 
Islands resides in its role in the formation of 
a dry forest cover and in the consequent 
checking of soil erosion. On most of the is- 
lands the dry forest region has been partially 
or completely denuded, with serious conse- 
quent erosion. Reforestation work has been 
carried out chiefly with quick-growing exotic 
trees such as Casuarina and Eucalyptus, but the 
appearance of the resulting vegetation is dis- 
appointing from an esthetic point of view. It 
is to be hoped that eventually the original dry 
forest trees, such as native species of Dio- 
spyros, Acacia, Sophora, and Myoporum, will 
regain a part of their lost dominance. Egler 
(1947: 425), studying the communities of the 
dry southeastern section of the Koolau Range 
on Oahu, predicted that although Myoporum 
was rare at that time it might in the future as- 
sume an important place in the Prosopis com- 
munity. 
Acknowledgments: Dr. Harold St.John of the 
University of Hawaii originally suggested this 
study, made it possible to collect and observe 
the plants in the field, and has been of great 
assistance in criticizing and offering sugges- 
tions for the manuscript. Mr. Otto Degener 
loaned his large and important collections for 
study and discussed with me some of the 
forms which I was unable to see in the field. 
Dr. B. C. Tharp readily consented to having 
the study continue at the University of Texas, 
and he and Dr. W. Gordon Whaley kindly 
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