a 
MARSH AND SAVANNA VEGETATION. 5 
MARSITES. 
The fresh-water marshes are usually overgrown with reeds (7?richoon 
rorburghi), associated with the great marsh fern (Acrostichum aurenm) 
(Pl. IV), the climbing Lygodium scandens, and several coarse grasses 
and sedges. The only trees are (ariti tiliaceum and a euphorbiaceous 
tree called ‘‘alom,” probably a species of Echinus. Growing about 
the margins of swamps are the small Bacopa monniera, x creeping 
scrophulariaceous plant with blue flowers and the habit of growth of 
purslane; Ambudia ‘ndica and A. fragrans, with an aromatic, camphor- 
like odor; Centella asiatica, the Asiatic pennywort; Aeschynomene 
indica; a species of Polygonum; and the water fern (Ceratopteris 
gaudichaudii), which has edible fronds. Several large aroids occur 
both cultivated and growing spontaneously, among them the common 
taro (Caladium colocasia), the caulescent Alocasia indica, and Alocasia 
macrorhiza. The introduced abaka, or ‘* Manila hemp” (A/usa tertilis), 
grows in several places, but it is not now cultivated by the natives. 
At least two species of bamboo grow on the island, the most useful 
and durable of which (Bambos blumeana) is armed with recurved 
spines and forms impenetrable thickets in several places. 
SAVANNAS, 
These are grassy upland regions almost devoid of trees and shrubs. 
They are characterized by a red clay-like soil and lack of drainage, 
and by the reappearance of beach plants and marsh plants which are 
absent from the forests. A7/pheagrostis floridula, which covers large 
areas, is called ‘* sword grass” by foreigners on account of the cutting 
scabrous edges of its leaves (PI. LXIX). It grows higher than a man’s 
head and offers refuge for deer. Roofs thatched with this grass are 
more durable than those of coconut or of nipa palm leaves, but more 
work is necessary in their preparation and they are not common 
except in regions where coconuts and nipa palms are scarce. Other 
savanna plants are the bracken-like fern G/eichenia dichotoma (Pl. L), 
Odontosoria retusa, Schizoloma ensifolium, Blechnum orientale, Pteris 
biaurita, Lycopodium cernuum (Pl. V), (the wawae tole, or ** rats- 
foot” of the Hawaiians), and the little golden star grass //ypoxis 
aurea. The only tree is the ironwood (Casuarina equisetifolia), which 
also grows on the margin of the sea. Among other beach plants 
which reappear here are the shrubs Lobelia koenigii, Pemphis acidula, 
and Melastoma marianum, the composites Stemmodontia biflora, 
S. canescens, and the Bidens-like Glossogyne tenuifolia,; also the 
grasses Dimeria chloridiformis, Stenotaphrum subulatum, and Cento- 
theca lappacea. The pretty little climbing marsh fern Lygodéum 
scandens is common, and the lavender-flowered morning glory /pomoca 
chorsiana also occurs. 
