APPENDIX 573 



not come under my notice on the beaches of North Chile, and it is 

 apparently not mentioned by Gay in his work on the Chilian flora. 



Convolvulus sepium, the frequent inland associate of the littoral 

 C. soldanella over the temperate regions of the globe, belongs to the same 

 section of the genus (Calystegia). Its extraordinary occurrence by itself in 

 the island of St. Paul, in the Southern Ocean, about fifty yards from the 

 shore (Bot. ChalL Exped.^ ii., 153, 264), almost suggests that we have here 

 a dimorphic species with a littoral and an inland form ; and its existence in 

 the Azores is in this connection very remarkable. It may be here noted 

 that of three plants raised from seeds found in the beach-drift near 

 Palermo two had the foliage of C. sepium and one of C. soldanella. 

 Perhaps one of my readers, in imitation of De Vries with (Enothera, might 

 be able to settle this point by raising some hundreds of seedlings from the 

 seeds of the beach species. It is possible that the relation between these 

 two species of Convolvulus may be in some respects akin to that between 

 Caesalpinia Bonducella and C. Bonduc, two littoral plants that accompany 

 each other over much of the tropical zone. 



The student of dispersal will, however, find some curious gaps in 

 the distribution of Convolvulus soldanella even in the temperate regions ; 

 and it will be curious to observe how they affect the distribution of 

 C. sepium. He will have to answer the query of De Candolle : . . . 

 " Admitting, if one wishes, that the currents have transported this marine 

 species, how comes it that it chances to be in the Pacific and in Europe, 

 without occurring on the east coasts of America and on the east and west 

 coasts of Africa?" (Geographic Botanique^ ii., 1056). He will have 

 to explain why some botanists give C. soldanella a habitat in the tropics, 

 as in the Indian region. Schimper, who investigated this point, says that 

 he arrived at no certain result (p, 127). See Notes 13 and 41 and pages 

 29, 91, for further remarks on these two species of Convolvulus. 



NOTE 50 (pages 79, 132) 

 ON THE STRUCTURE OF THE SEEDS AND FRUITS OF BARRINGTONIA 



As regards the fruits and their coverings, the littoral and inland species 

 of Fiji evidently fall into different sections, the first named (B. speciosa 

 and B. racemosa) being distinguished by their outer fibrous husk, to which 

 the buoyancy is due, the last-named (B. edulis and an undescribed species) 

 possessing a hard stone surrounding the seed, and here the fruits sink or 

 float only for limited periods. 



The fruits of B. edulis have an outer almost fleshy covering, a little 

 fibrous at the outside, and the hard ligneous " stone," containing an edible 

 seed, requires a hammer to break it. They float heavily for three or four 

 weeks, whereas those of the littoral species float for many months. In the 

 case of another inland species found by me growing as a small tree 1 2 feet 



