THE GENUS MORINDA IN THE HAWAIIAN FLORA 



VAUGHAN MacCAUGHEY 

 College of Hawaii, Honolulu, Hawaii 



The Hawaiian flora presents many interesting problems to the 

 student of plant distribution. A very high percentage of the 

 native vegetation is endemic — a larger percentage, in fact, than 

 occurs in any other region of like area. The search for evidence 

 bearing upon the origin of these endemic forms is one of the out- 

 standing problems of the phytogeography of the Pacific region. 



An excellent instance of the local peculiarities in plant distri- 

 bution is the rubiaceous genus Morinda. This genus, (Sphaero- 

 phora BL, Guttenbergia ZolL, Rennellia Korth., Tribrachya 

 Korth., Imantina Hook, fil.), of shrubs, trees, and small climbers, 

 comprises about 60 described species. A few of the species are 

 epiphytic. The generic name is from the Latin niorus, mul- 

 berry, and Indica, Indian, and several of the species are known 

 popularly as "Indian mulberry." The East Indian name is ach. 

 The genus is distributed through tropical Asia, Australasia, and 

 the islands of the Pacific; there are a few forms in tropical 

 America and Africa. Most of the species occur in southwestern 

 Asia; as one travels eastward through Malaya, Australia, and 

 the Central Pacific, the representation rapidly diminishes, and 

 in the isolated Hawaiian Archipelago there are but two species,^ 

 one introduced and the other endemic. Several fossil species 

 have been reported from the Tertiary of Europe; the total num- 

 ber is about seven. 



The characters of the genus are briefly as follows: Leaves 

 opposite, rarely in 3's. Stipules membranous, connate inside the 

 petioles. Flowers sessile, in small, globose heads, which are axil- 

 lary or terminal, simple, panicled, or umbellate. The flowers are 



^The Yaw-Weed, M. Roioc L., a native of Florida and the West Indies, does not 

 occur in Hawaii. It is a prostrate branching shrub with small crimson flowers. 



209 



