FLORA OF THE GROUP. 193 



sixty species distributed over two hundred aud sixty-five genera that are to be 

 regarded as the original inhabitants of Hawaii. Of this number more than six 

 hundred and fifty species are found nowhere in a natural state outside of Hawaii 

 and are therefore endemic, precinctive or peculiar to the group. 



The number of endemic plants found on the difi'erent islands of the 

 group varies in a way contrary to what might naturally be expected, as the 

 number is largest on Kauai and smallest on the large island of Hawaii. This 

 seems to be in accordance with geologic facts. Since, as has elsewhere been 

 said, Hawaii as a whole is regarded by geologists as the youngest of the islands 

 geologically, it is reasonable to conclude that the niunber of endemic plants oc- 

 curring on it, or on any of the islands, furnishes a fair index to the relative age 

 of that particular island. Thus Kauai, which stands fourth in area, stands 

 first in her list of species, and the species are as a rule much better defined 

 than are those on the younger islands of the group. 



]Much that is interesting has been learned by tracing the orgin and affinities 

 of the plants of the Hawaiian group. This is done by carefully following out 

 the relationship of the various genera, families and orders with a view to finding 

 if possible the place from which they have been distributed in times past. Since 

 there are no fossil plants in Hawaii it is necessary to rely entirely on the geo- 

 graphical method of determining the source and relationship of the native flora. 



If the two-thirds of the list of the plants that are found nowhere else be 

 left out of account, we find that the remaining one-third has come from various 

 sources, in many instances far remote from the islands, by routes often diffi- 

 cult to trace. On the other hand there are species that are widely distril)nted 

 throughout Po]^^lesia that are only allied to American forms. J\Iany others are 

 of Asiatic origin with Polynesian affinities. A small number have been con- 

 tributed by Australia, while a limited number are of African origin. Still 

 other species are almost world-wide in their distribution. 



Yari.vtion in the Flora from Island to Island. 



The plant life of the several islands of the group not only varies as to the 

 character of the flora found on each, but each individual island varies in its 

 flora in different localities to a cei'tain extent, showing adaptations that accord 

 with variations in altitude, soil, wind and the amount of rainfall. This is true 

 to such a degree that no two valleys will have exactly the same plants, and 

 each excursion into the mountains is liable to be rewarded by bringing to light 

 something not seen elsewhere and possibly not even known heretofore in the plant 

 world. 



(Description of Plate Continued from Opposite Page.) 

 diffusa), see also No. 7. 5. Pauohiiaka (Jacquemontia Sandwwensis). 6. La Platte Tobacco 

 (Xicotiaim plauca). 7. Alena {Boerlmavia diffusa). 8. Nohu {Trihulus cistoides). 9. 

 Akoko {Euphorbia cordata). 10. Maiapilo (Capparis Sandwicltiana). 11. Pili (Andropo- 

 gun = (Htti-ropofion) contortu-l). 12. Beach Sandalwood [Iliahi] {Santalum Frciiciiictianum 

 var. Uttorale). 13. Beach Morning-glory [Pohuehue] {Ipomoea pes-caprce) . 14. Beach grass 

 (Sporobolus rirginicus). 1.5. Five-fingered Morning-glory [Koali ai] (Ipomoea tuherculata) . 

 16. Carex sp. 17. Akulikuli (Sesuvium Portulacastrum) . 18. Alaalapuloa {Waltheria 

 Americana). 



