AFRO-INDIAN REGIONS. 



385 



diately back of Honolulu, and is commonly called Punch-bowl Hill. 

 A third coast-crater, in sight some miles to the Westward, and beyond 

 the mouth of Pearl River, was not visited. Besides these, the remark- 

 able salt-lake in the last-named vicinity was regarded by Mr. Dana as 

 occupying one of the three basins of an "old crater;" the other two 

 presenting also saline traces, and the whole hardly less than three 

 miles in diameter, with the partition-ridges higher than the common 

 encircling rim : on the Windward side of the Group, this would pro- 

 bably have been filled by the rains and broken through, to the wash- 

 ing away of all depositions and traces of salt. 



The Desert environs of Honolulu present no genuine Desert plants; 

 the area of denuded soil being very limited, both here and throughout 

 the Group. Tribulas cistoides, a Zj'gophyllaceous plant, seemed indeed 

 entirely at home ; but the species is not peculiar to the Hawaiian 

 Islands, and may even have been introduced through human agency. 

 The Leeward Portion of Oahu, and of the Group generally, is thinly 

 coated with grasses and herbaceous or subherbaceous plants; bearing 

 the impress of aridity in their greyish color, and in the prevailing 

 want of freshness. Grasses predominating : especially the Heteropogon, 

 exclusively occupying a large proportion of the surface ; giving place 

 at intervals to extensive tracts of tufts of an EragrcMis three feet high. 

 Next to the grasses, the Waltheria seemed the most frequent plant; 

 and then, three or four Sidas, all differing from the species of Southern 

 Polynesia; and an AcJnjrantlies, a characteristic plant, remarkable for 

 turning conspicuously yellow in drying. Gen. Ahutilon-like with rose- 

 colored flowers, is more rare ; as also, the velutinous Gossypkan ; the 

 Chenopodium having a sufFruticose or even woody base ; the purple- 

 flowered Portulam, and the yellow-flowered species ; the clustered 

 white-stemmed Wedelia? ; the shrubby Ccenofus?; and the prostrate, 

 small-flowered Ipomcea. — Six months later, on revisiting Oahu at the 

 close of what was called the " winter" or " wet season," the Leeward 

 side of the island presented a decidedly fresher aspect. Some tracts 

 indeed, remaining Desert, and bare of vegetation as before. In the 

 absence of annual plants, a crop of young Sidas had sprung up on por- 

 tions of the denuded district, with but a slender prospect of ever attain- 

 ing maturity. 



Oahu contains two mountain-ridges; hardly at any point exceeding 

 three thousand feet in elevation, and separated by a wide intervening 

 grassy plain. One of these, the mountain-ridge of Mauna Kaala, 



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