Heller: plants of the Hawaiian islands. 763 



through the soil and makes its appearance as streams some- 

 where upon the lower slopes of the mountains, or wells up as 

 springs on the beach. Along the beach, between Diamond 

 Head and Koko Head, on Oahu, in a region where rain rarely 

 falls except in winter, are a number of springs of fresh water, 

 covered at high tide by the sea. Just beyond Diamond Head 

 it is a common sight to see cattle go down to the beach, and 

 apparently take a drink of salt water. 



Judging from the uniformity of the geological formation, we 

 should expect a great similarity in the vegetation of the several 

 islands, but such is not the case. True, there are many species 

 common to all of the islands, but the bulk of the native species 

 found on any given island, are different from those which occur 

 on the other islands, and when a species is found on two or 

 more islands, it differs somewhat in leaf form, or in some other 

 particular. This is especially true of strictly endemic plants. 

 The introduced species show a much greater uniformity in 

 habit and growth. 



Isolated from a continental area, and almost equally so from 

 the other islands of the Polynesian system, Hawaiian vegeta- 

 tion has developed independent of extraneous modifying con- 

 ditions. That it has done so in a satisfactory way, is evinced 

 by a summing up of the proportion of endemic species in Hille- 

 brand's Flora. This work, published in 1888, enumerates 999 

 species of phanerogams and vascular cryptogams. Of this 

 number, 139 are introduced, and 653 are endemic, leaving 207 

 native species which are found elsewhere. 



Of the 653 endemic species, 250 belong to 40 endemic genera. 

 These endemic genera are found principally among the Rubi- 

 aceae, Compositae, Lobeliaceae, and Labiatae. The dis- 

 tribution of the species in the iarger of these endemic genera 

 is quite interesting. 



Schiedia is represented on all of the islands, but principally 

 on the northern islands of Kauai and Oahu. The same holds 

 good, too, with Pelea and Platydesma. 



Of the Araliaceae, Cheirodendron is pretty well divided. 

 Dipanax is northern, one species out of three being found on 

 Lanai. Triplasandra is confined almost exclusively to Oahu. 



Of the Rubiaceae, Kadua, Gouldia, Bobea, and Straussia are 

 distributed over all of the islands, but Hawaii has a smaller 

 number than the other islands. 



In the Compositae, Remya is, found on Kauai and Maui, with 

 no species recorded from the intermediate island of Oahu. 



