374 A NATURALIST IN THE PACIFIC CHAP. 



One of the mysteries of the Pacific is concerned with the dis- 

 tribution of the Sapotaceae, the dispersal of which by frugivorous 

 birds has been dealt with above. It is strange that whilst the 

 order seems to have found a rendezvous in Tonga, no one except 

 Home appears to have recorded any of the genera from Samoa. 

 They are fairly well represented in Fiji; but it is in Tonga that we 

 especially note the gathering together of several Sapotaceous trees 

 with large heavy seeds, of the genera Bassia, Mimusops, and 

 Sideroxylon. Besides owning one or two species of Sideroxylon 

 in common with Fiji (Burkill), this small group possesses Bassia 

 amicorum and Mimusops kauki, both of which were found there by 

 Forster at the time of Cook's visit. In a list of a small collection 

 of plants made by him in Upolu in the Samoan Group about 1879, 

 Home includes two species of Sideroxylon ( Year in Fiji, p. 286) ; 

 and according to Seemann there is a Sapotaceous tree in Wallis 

 Island. A species of Bassia exists in Rarotonga, the seeds of 

 which, from Mr. Cheeseman's description of the fruit, must be 

 almost an inch long. Drake del Castillo refers to an endemic 

 Tahitian tree near Mimusops ; but its fruit was not known to 

 him. 



As already indicated, the difficulties connected with the 

 Sapotaceae affect the whole Pacific from New Zealand north to 

 Hawaii and from Fiji east to Tahiti. We are driven to appeal to 

 the agency of frugivorous birds, at least in the case of Sideroxylon, 

 since some fruits experimented on by me in Fiji sank at once or in 

 a day or two, the seeds having no buoyancy. That birds actually 

 disperse the seeds of this and other genera of the order has been 

 already pointed out, yet it is possible that currents have at times 

 aided in the dispersal of some of the genera. This is indicated 

 by the circumstance that, as we learn from Schirnper, some 

 Sapotaceous trees are to be included in the Malayan strand-flora, 

 namely, Sideroxylon ferrugineum, Mimusops kauki, and M. littoralis, 

 all occurring as well on the Asiatic mainland, the first growing also 

 in the Liukiu Islands, and the last in the Andaman and Nicobar 

 Groups. 



Ruppia maritima (Potamese). This cosmopolitan aquatic 

 plant has only been recorded in Polynesia from Hawaii, Samoa, 

 and Fiji. It had not been collected in Fiji before my dis- 

 covery of it in 1897. Amongst other oceanic islands where 

 it occurs may be mentioned the Bermudas, where, according to 

 Hemsley, it exists as an indigenous plant in the lagoons. 

 Chamisso first noticed it in Hawaii, and Hillebrand remarks that 



