DISPERSAL OF PLANTS BY OCEAN CURRENTS. 75 



Fruits with buoyant husks. — In addition to tlie coconut, which 

 is provided with a fibrous envelope, and is l^nown to tloat for h)nji- 

 periods of time in the sea witliout losing- its vitality, there are found 

 in the drift of Guam the fruits of Barrlngtonia speciosa^ called ''put- 

 ing" by the natives, and Ochrosia marimuiensis, called " fago.'' Both 

 of these fruits have fibrous husks, but that of the Barringtonia has a 

 hard glossy surface, somewhat as in the case of the coconut, while the 

 surface of the Ochrosia is soft and easily eroded. The fruits of this 

 Barringtonia (PI. XXXVIII) are four-cornered and miter-shaped; 

 'he natives crush them and use them as a fish intoxicant. Those of the 

 Ochrosia are oval in shape, and, like the closely allied Cerbera fruits 

 of Samoa and other tropical countries, are soon deprived of their pulpy 

 parenchyma, and display the cushion of fiber inclosing the mesocarp. 

 This owes its buoj^ancv to intercellular air spaces. It is elastic and 

 serves to protect the seed from erosion and from the attacks of animals. 



Mangrove fruits. — Great numbers of these spindle-shaped young- 

 plants are continually carried by the tide from the estuaries into 

 which the}' drop after having- begun to germinate on the tree. The 

 fruits of Rhlzopliora mucronata (PI. LXIV) are easily distinguished 

 from those of Bruguiera gymnorhka (PI. XL) by the four-parted 

 persistent calyx, the calyx of Bruguiera consisting of many segments. 

 Associated with them are found the seeds of the "red-flowered 

 mangrove" {Lumnltsera llttoreu)^ called "nana" in Guam; those of 

 Excoecaria agalJoeha^ the "milky mangrove," or "blinding-tree," 

 which grow in catkin-like spikes; and the keeled nuts of the "ufa" 

 {llerititra IlttoraHs), the hard shell of which includes a very large 

 air space (PI. LII). 



Littoral trees and shrubs. — Other seeds found in the drift are 

 those of Pariti tiliacenin and TlieHpe^m popnlnea^ the "pago" and 

 "kilulu" of the natives, both of which l)elong to the Malvaceae, and 

 have cavities filled with air; the round nuts of CkdophyUuia hiophyl- 

 lian^ called "daog;" the boat-shaped "almonds" of Teriainalta catappa, 

 called "talisai," often much eroded; the angular woody seeds of the 

 "lalanyug" {Xylocarpus granatum)^ and the ril)bed fruit of the nipa 

 palm {Nypa fndicans). Among the plants which grow on the edge of 

 the sea, whose fruit drops into the water continually, are the shrub])y 

 Lohelid A'oenigli and Tournefortla argentea (PI. LXVIII), associated 

 with the creeping "goats-foot convolvulus"' {Ipomoect, pes-cap'me), the 

 seeds of which contain air cavities, and the "Polynesian ironwood" 

 {Casuarhia equisetifolia), the cones of which (PI. XLI) are corky and 

 buoyant and inclose seeds provided with wings which adapt them for 

 transportation by the wind. The transparent wings of these seeds are 

 stifi'ened ])y the persistent style. When a handful of them is thrown 

 into the air the}- resemble a swarm of fl.ying insects. Hundieds of 

 these seeds, together witli the queei-shaped Barringtonia fruits, are 



