MARSH AND SAVANNA VEGETATION. 57 



MARSHES. 



The fresh- water marshes are usually overo^rown with reeds {Trie hoon 

 roxhmyhu), associated with the great marsh fern {Aerostichmn aureum) 

 (PL IV), the climbino- Lygodluin scandens^ and several coarse grasses 

 and sedges. The only trees are Parltl tiUaceum. and a euphorbiaceous 

 tree called "alom," probably a species of Echinus. Growing a])out 

 the margins of swamps are the small BaeojMi monniera^ a creeping 

 scrophulariaceous plant with blue flowers and the habit of growth of 

 purslane; Andndia indiea and ^1. fragravs^ with an aromatic, camphor- 

 like odor; Centella asi<dla(^ the Asiatic pennywort; AeHchynoniene 

 indiea; a species of Polygonum; and the water fern {Ceratopterin 

 gaudlchaudii)^ which has edi))le fronds. Several large aroids occur 

 both cultivated and growing spontaneously, among them the common 

 taro ( Caladium, colocasia), the caulescent Alocasia indiea^ and Aloeasia 

 raacrorliiza. The introduced abakii, or "Manila hemp"" {Musatextilis)^ 

 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 {Bamhos hhnneana) 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 reapj^earance of beach plants and marsh plants which are 

 absent from the forests. Xipheagi'ostis jloridida^ 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. Koofs 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 OleicKenia dicTiotoma (PI. L), 

 Odontosoria retusa, Schizoloma ensifoluiin^ Blechnum ryrientale, T^eris 

 hiau7'ifa, Lycopodium cernuimi (PI. V), (the waivae iole^ or "rats- 

 foot" of the Hawaiians), and the little golden star grass Ilypoxis 

 aurea. The only tree is the ironwood {Casuarina equiseti folia), which 

 also grows on the margin of the sea. Among other beach plants 

 which reappear here are the shrubs Lobelia hoenigii^ Pemplik aeklida^ 

 and Melastoma inarianuin; the composites Stemmodontia hiflmri^ 

 S. canescens^ and the Bidens-like Glossogyne tenuifoUa; also the 

 grasses Dimeria chloridifoi'mis, Stenotaj)hrum, svhidatmn^ and Cento- 

 theca lappaeea. The pretty little climliing marsh fern Lygodium 

 scandens is common, and the lavender-flowered morning glory Ipomoea 

 choisiana also occurs. 



