io6 A NATURALIST IN THE PACIFIC chap. 



S. Dodonaea viscosa. 



G. Argyreia tiliaefolia, variable. 



G. Ipomea bona nox, variable. 



G. Ipomea glaberrima, Boj. 

 S. G. Ipomea grandiflora. 

 S. G. Ipomea pes caprae. 



G. Ipomea turpethum, variable. 



G. Cassytha filiformis. 



S. Euphorbia atoto. 



Notes. — The species marked " variable " have seeds that some- 

 times sink and sometimes float. With the exception of Kleinhovia 

 they are only at times littoral in station. 



The plants of the British flora are represented by Convolvulus 

 soldanella and C. sepium, the last being " variable " and not a 

 littoral species. 



Section II. All the seeds belong to the Leguminosae. 

 Neither the tests nor the seed-contents have any 

 buoyancy, the floating power arising from a large 

 central cavity produced by the bending outward of 

 the cotyledons during the final shrinking stage of the 

 maturation of the seed. 



S. Mucuna (generically). 

 G. Mucuna urens D.C. (Hawaii). 

 G. Mucuna, species of. 

 S. G. Vigna lutea. 

 S. G. Caesalpinia bonducella. 

 G. Caesalpinia bonduc. 

 G. Entada scandens. 



Sub-group II., where the fruit is concerned. 



Section III. The seed only partially fills the fruit- 

 cavity, and as a rule is not buoyant. The fruit shell, 

 usually woody, may be also buoyant. 

 S. G. Heritiera littoralis, 

 G. Smythea pacifica. 

 G. Dalbergia monosperma. 

 S. G. Derris uliginosa. 

 S. G. Pongamia glabra. 



G. Desmodium umbellatum. 

 G. Gyrocarpus jacquini. 



