Oliver. — Vegetation of the Kermadec Islands. 151 



(end.), Veronica hreviracemosa (end.), Mariscus ustuJatus, Le-pidium oleraceum 

 frondosum, Carex Forsteri insularis, and 16 plants of lesser importance, one 

 of which is a fern. 



The Polynesian element in the Kermadec Islands flora is considerable, 

 and characterizes the group as belonging to a distinct province of the New 

 Zealand biological region. Of the 28 species not common to all the regions 

 under consideration, 6 extend to Lord Howe and Norfolk Islands (one or 

 both), 9 to New Zealand, and 3 to both places. This leaves 10 purely Poly- 

 nesian species, of which 4 are ferns (including Cyathea kermadecensis). The 

 remaining 6 are Homolanthus pohjandrus (end.), Ascarina lanceolafa (end.), 

 Sccevola gracilis (end., but affinities uncertain), and 3 grasses — Imperata 

 Cheesemani (end.), Eleusine indica, Cenchrus calyculatus. Of the 9 species 

 extending to New Zealand, 7 are ferns, 1 is Coprosma acutifolia (end.), and 

 the other Kyllinga hrevifolia (possibly introduced). Compared with the 

 New Zealand species, the Polynesian forms in the Kermadecs must be con- 

 sidered weak. 



[h.) The Subtropical Islands Province. 



It remains to point out the relation of the Kermadec Islands plants 

 to those of Lord Howe and Norfolk Islands. Excluding the 34 widely 

 spread species, 34 Kermadec Islands plants are found in Lord Howe and 

 Norfolk Islands (one or both). Of these, 22 occur in New Zealand, 6 in 

 Polynesia, and 3 in both of these regions. The remaining 3 species are 

 confined to the three groups of islands forming the northern province of 

 the New Zealand region. They are Rhopalostylis Baueri, Rapanea ker- 

 madecensis, and Boehmeria dealbata. These plants enter largely into the 

 forest on Sunday Island, and, while Rhopalostylis Baueri is found on Norfolk 

 Island, the others are endemic, but closely related to Norfolk Island forms. 

 The New Zealand species include Coprosma petiolata (end.), 4 ferns, Scirpus 

 nodosus, Heleocharis acuta, Microtis unifolia, Parietaria debilis, Peperomia 

 Endlicheri, and 12 others not taking prominent parts in the plant formations 

 of Sunday Island. The 6 Polynesian species are Metrosideros villosa, Ipomoea 

 pes caprce, Canavalia ohtusifolia, 2 ferns, and Panicum sanguinale microhacJine. 

 Those common to both New Zealand and Polynesia are Melicytus ramiflorus, 

 Macropiper excelsum, and Diplazium japonicum. 



The greater part of the vegetation on Sunday Island is thus composed 

 of plants extending to (or closely related to species in) Lord Howe and 

 Norfolk Islands (one or both), and, of these, Metrosideros villosa, Rho- 

 palostylis Baueri, Rapanea kermadecensis, Boehmeria dealbata, Ipomoea pes 

 caprce, and others do not occur in New Zealand. Dr. Cockayne has drawn 

 my attention to the large proportion of Norfolk Island forms in the New 

 Zealand species found in the Kermadecs. Of the New Zealand plants 

 on Sunday Island, 54 per cent, are also found in Norfolk Island, but of the 

 total number of species in New Zealand only 8 per cent, extend to Norfolk 

 Island. It is probable, then, that a number of the Kermadec Islands plants 

 occurring in both Norfolk Island and New Zealand arrived from Norfolk 

 Island direct ; but the above figures do not express the relations quite 

 correctly, as the whole of the New Zealand flora is made the basis of the 

 calculation, instead of the North Island, whence only New Zealand plants 

 could be expected to migrate to the Kermadecs. 



No doubt climate determines which species shall establish themselves ; 

 hence in Lord Howe, Norfolk, and Sunday Islands, which are in nearly the 

 same latitude, a large number of the species (48 to 60 per cent.) in each 



