208 NATURAL HISTORY OF HAWAII. 



Watercress ^^ is in reality a species of Nasturtium. It was an early arrival 

 and has spread in the streams about Honolulu and the islands generally. It is 

 the same species as that so much esteemed as a food in Europe. While it flour- 

 ishes in Hawaii and is especially fine in flavor, it rarely flowers. The air-plant ^« 

 is another escaped plant. It grows two to five feet tall with erect fleshy stems 

 and large, thick, ovate leaves, and has green bell-shaped nodding flowers tinged 

 with reddish yellow. The air-plant is a familiar species in suitable localities 

 of the lower levels. While it is a native of Africa, it flourishes here and is a 

 well known curiosity owing to the fact that a leaf left lying on the table will 

 begin to grow from the crenate notches along its edge, apparently deriving its 

 sustenance from the air. 



Gr.vsses. 



Grasses of various species, both native and introduced, form the principal 

 field vegetation of the costal region. No fewer than three dozen genera of 

 grasses have been recognized in Hawaii by botanists. Many genera foixnd in the 

 lowlands enjoy a considerable range, extending well up into the mountains, and 

 have numerous species of more or less nnportance. Of the genus Panicum fifteen 

 species and several doubtful varieties have been recorded by Hillebrand and 

 others They are found in various places i;nder varying conditions throughout 

 the group. At least a half dozen and perhaps more introduced species belong- 

 ing to this genus are common in the cultivated districts. 



The original manieiiie ^" that formerly occupied the lowlands up to 2,000 

 feet elevation, belongs to a different genus from the creeping grass introduced 

 in 1835 which is the familiar grass *^ of the yards about the city. The former 

 is a coarser grass creeping with ascending branches six to eight inches long 

 bearing four to eight pairs of leaves. The latter has slender rooting stems, with 

 four to eight pairs of alternate leaves with three to six spikes, an inch or more 

 long, at the end of the stem. Owing to its creeping habit it has been called by 

 the natives manienie. It forms a dense mat in pasture lands and has crowded 

 out other grasses up to the upper limit of the lowland zone. It is of great 

 use in dry, sandy pastures as it binds down the soil and thrives where other 

 grasses fail, since its roots penetrate deep down in the loose soil. Like the 

 algaroba tree, which is a similar fortuitous introduction occupying this zone, 

 it is a most valuable acquisition to the island flora from every point of view. 



Two species of Paspalum occur in this zone; one, the well known and 

 generally despised Hilo grass,^^ occurs in moist, heavy soils in the lower zone and 

 grows well into the higher regions in suitable places. The Hilo grass, which is 

 an introduced species as has been said, has crowded out almost every other 

 species of grass where it has gained a foothold. It is a large, rank grass, taller 

 than the native species, growing two to four feet hmh. and has two spikes at 



*^ Bryophyllum calyc 

 ' Paspalum conjugatum 



