xxvn NAIAS 367 



1,800 or 2,000 miles of sea ; and we may have to choose between 

 the bird and the current in selecting the agency concerned with 

 the transportation of the original seeds ; or perhaps they have 

 co-operated. Birds could disperse the nutlets of Rumex as readily 

 as they do those of Polygonum, and I have found these fruits at 

 times in the stomachs of partridges. On the other hand, Rumex 

 fruits occur amongst the drift stranded on beaches in England and 

 in Scandinavia ; and, as indicated by the observations of Sernander 

 and myself in these two localities, they float through the winter in 

 ponds and rivers, germinating afloat in the spring. The nutlets 

 sink, but they owe their buoyancy to the persistent perianth. In 

 my sea-water experiments the fruits of Rumex hydrolapathum and 

 R. conglomeratum were still afloat after from six to twelve months' 

 immersion, and their seeds subsequently germinated. It is quite 

 possible, therefore, that currents can carry these fruits unharmed 

 to oceanic island-groups like Hawaii and Tristan da Cunha. 



Dracana (Liliaceae). — This Old World genus, which on account 

 of its berries is eminently suited for dispersal by frugivorous birds, 

 is represented in Polynesia by a solitary species (D. aurea) peculiar 

 to the Hawaiian Group. Attaining a height of twenty to twenty-five 

 feet, it often forms a striking feature in the vegetation of the open 

 wooded regions up to altitudes of 3,000 feet. I found it growing 

 in abundance in the large island of Hawaii between Waimanu and 

 Waipio, and on the northern slopes of Hualalai. It grows in a 

 variety of stations, and I came upon it once in the broken-down 

 caverns of an old lava-flow that were frequented by pigeons which 

 no doubt brought the seeds. Its conspicuous yellow berries have 

 hard rounded seeds a quarter of an inch (6 mm.) across and weighing 

 two to three grains when dry, which would probably withstand injury 

 in a bird's stomach, the minute embryo being protected by a very 

 tough albumen. Neither the entire berry nor the seed could be 

 transported by currents, the last sinking even after drying for six 

 years. 



Naias (Naiadaceae). — If we except New Caledonia, where two 

 or three species have been found, Hawaii is the only island-group 

 in the tropical Pacific from which this interesting world-ranging 

 genus of submerged aquatic plants has been recorded. Chamisso, 

 the celebrated naturalist of Kotzebue's expedition, collected Naias 

 marina in Oahu in the early part of last century ; but apparently 

 it did not come under Hillebrand's observation in the group. 

 However, in 1897 I found it in another locality, namely, just within 

 the mouth of the Waipio, a river on the north-west side of the 



