•"322 Transactions. 



cuously, and as this ie an important phytogeographical matter 

 having a bearing on general plant geography, I am going into 

 the facts at some length. That some species have been more 

 widely spread on the mainland than at present is known in 

 some cases. Thus Lepidium oleraceum was so common ^t the 

 time of Captain Cook's visit that he fed his crew on it, calling 

 it " scnrvv-grass." This plant is now virtually extinct on the 

 mainland, but abounds on certain of the small outlying islands. 

 Sicyos australis* has become quite rare on the mainland, but 

 on the Little Barrier Island and other islands in the north it is 

 abundant, climbing higli up Metrosideros tomentosa or straggling 

 over Macropiper excdsum. The magnificent Meryta sinclairii is 

 wo longer to be encountered on the mainland, and is only 

 known from the Three Kings, where it is plentiful (8a), and the 

 Hen and Chickens. f If a plant, abundant on a far-distant 

 island, occurs very rarely or over an extreme^ limited area 

 ■on the mainland, it seems reasonable to conclude that it 

 was once much more widely spread, especially when geological 

 evidence proves that the island is the younger land. Thus 

 Suttonia chathamica, a common tree of the Chatham Island 

 forests (12; p. 277), was found by G. M. Thomson in one 

 statioji in the south-east of Stewart Island. Hymenanthera 

 ■chathamica, an equally common Chatham Islajid tree, has been 

 observed at one spot in the Wellington Province, North Island, 

 by Sir James Hector (34; p. 46). Other similar cases are: 

 Pratia arenaria, which is confined to the Southern Islands and 

 Chatham Island, where it is abundant in various formations ; 

 Urtica australis, common in both the last-mentioi\ed groups and 

 almost reaching the South Island, since it occurs on both Dog 

 and Centre Islands, in Foveaux Strait ; Archeria racemosa, 

 found on the n\ountains of both Great and Little Barrier 

 Islands and on the Coron\andel Ranges of the North Island ; 

 Stilbocarpa lyallii, common in Stewart Island, Ruapuke and 

 others of the Stewart Island group, but only recorded in the 

 'South Island from near Preservation Inlet. Lepyrodia tra- 

 versii, the most characteristic bog plant of the Chathams ( 12 ; 

 p. 287), and for a time thought to be endemic, is now known, 

 thanks to the researches of Cheeseman (7), to be abundant in 

 some of the Waikato swamps. The endemic genus Myosotidium 

 of the Chatham Islands was also probably much more widely 



* Kirk states (34; p. 183) that the plant on the outlying islands differs 

 in leaf-form from that of the mainland. If this is always the case, and the 

 two forms come true from seed, here is another example of an incipient 

 species. 



t During my recent visit to the Poor Knights Islands I saw no trace 

 of this tree (15). 



