Mauna Loa. The vegetation is extremely uniform, Ohia lehua being the only 

 tree, while in certain localities it is entirely bare of vegetation. 



At 5000 feet elevation is a large area of land with rich soil supporting a 

 number of species of native grasses, mainly Eoehleria glomerata, with Carex 

 sandivicensis var. lavarum. Most beautiful Koa trees of great size form clumps 

 of forests, together with Mamani. This land, which has been reserved as a pad- 

 dock, must be extremely old, as no lava is visible, and is sharply contrasted by 

 the rugged, sharp, black aa lava flows bordering it. Above this paddock, which 

 is of considerable extent, is the again everpresent lava. It is only on this side, 

 but mainly above Kapapala, that the silversword, Argyroxiphium sandwicense, 

 is found as low down as 7000 feet elevation on Mauna Loa. The vegetation from 

 the volcano until one reaches Hilea, in Kau, is extremely uniform and quite unin- 

 teresting. At Hilea, the slopes of Mauna Loa are cut into many divisions, mainly 

 valleys and ridges with very precipitous slopes. From Naalehu the country 

 slopes very gradually. 



FLORAL ASPECTS OF KAU. 



LAVA POBMATION. 



Immediately below Hilea proper the land is all under cultivation, sugar cane 

 being the only crop. At an elevation of about 2000 feet is a small plateau, 

 mainly composed of pahoehoe lava of apparently great age, on both sides the 

 mountain of Kaiholena rising to about 1000 feet, with very precipitous walls. 

 The pahoehoe plain, which is called Kanalohu, is all hollow underneath. Great 

 subterranean channels undermine the whole plain, and are now used for reser- 

 voirs. The lava walls are perfectly smooth and black and form complete arched 

 tunnels for a long distance. These were undoubtedly subterranean outlets of 

 rushing lava streams. In fact, some of the channels can be traced right down 

 to the water's edge. The main vegetation of this plateau is Paspalum conju- 

 gatum (Hilo grass), besides a number of ferns. 



Emerging into this flat plateau are several valleys, one of which, Kumauna, 

 is of interest. The forest from Plilea to Waiohinu, though being on the lee side 

 of Hawaii, belongs to the rain or wet forest type. At Hilea proper it is somewhat 

 mixed, being composed of trees belonging to both wet and dry forest types. The 

 forest as a whole is more uniform than similar forest types in other localities, 

 due mainly to the land being geologically much younger than in similar locali- 

 ties on the other islands where volcanic activities ceased thousands of years 

 ago, as it is situated on the southern slopes of the still active volcano Mauna Loa. 

 The land, nevertheless, has extremely rich soil, which is black and somewhat 

 muddy. The principal tree of which the Hilea forest is composed is Metrosideros 

 polymorpha, which is the most numerous. Its associates are Antidesma platy- 

 phyllum (Rame), Straussia, Perrottetia sandwicensis (Olomea), Pipturus, Sut- 

 tonia (Kolea), Pelea volcanica, Pelea clusiaefolia, Bobea sp., Tetraplasandra 



33 



