16 



M. robusta, Myrtus bullata, x M. Ralphii, Eugenia maire; 

 (Halorrhagaceae) Myriophyllum robustum; (Epacridaceae) 

 Epacris pauciflora, Dracophyllum lati folium; (Oleaceae) Olea 

 Cunninghamii, O. lanceolate, O. montana; (Myrsinaceae) 

 Rapanea salicina; ( Logariiaceae) Geniostoma ligustrifolium 

 (Scrophulariaceae) Veronica speciosa, V. salicifolia var. 

 Atkinsonii, V. parviflora, V. gracillima, Euphrasia cuneata; 

 (Rubiaceae) Coprosma retusa, C. tenuicaulis, Nertera Cunning- 

 hamii; (Caprifoliaceae) Alseuosmia quercifolia; (Cucurbita- 

 ceae) Sicyos australis; (Compositae) Olearia Cunninghamii, 

 Gnaphalium subrigidum, Cassinia leptophylla, Brachyglottis 

 repanda. 



This list together with that given for latitude 38deg., almost 

 exhaust the North Island element of the New Zealand forest 

 flora 19 , but Banks Peninsula is the southernmost halting-place 

 for a few more species (e.g., Alectryon excelsum, Adiantum 

 fulvum, Corynocarpus Io2vigata, Dodonoea viscosa, Griselinia 

 lucida, Leucopogon fasciculatus, Macropiper excelsum, Mariscus 

 ustulatus, Rhopalostylis sapida, Tetrapathcea australis and 

 Zoysia pungens. On the west, those most common species of 

 North Island forests Astelia Cunninghamii, Metrosideros 

 florida and M. scandens are a characteristic feature of the 

 forest of the Western Botanical District as far south as Okarito, 

 at any rate ; so too is Freycinetia Banksii, which extends further 

 south into the Fiord Botanical District. The North Island 

 tree-ferns, Cyathea Cunninghamii and Dicksonia lanata, are 

 also found in some localities of the Western District. 

 Hedycarya arborea, on the east, has its southern limit on Banks 

 Peninsula, but on the west it extends as far south as Preserva- 

 tion Inlet. 



(c) The effect of the Southern Alps and the Coastal Mountains of 

 North-western Nelson on plant-distribution. 



The mountains situated at so short a distance from the 

 Tasman Sea near the west coast of the South Island cause the 

 moisture-laden westerly winds to deposit nearly all their 

 moisture, so that an extremely wet climate extends from the 

 coast-line to a definite point on the eastern side of the actual 

 Divide. This area in the lowland, montane, and lower-subalpine 

 belts is clothed with a dense forest-mass, but, at its eastern 

 boundary at a point marjdng the average limit of the western 

 downpour, it gives place, all on a sudden to tussock-grassland. 

 Frequently the rain extends to the very margin of the forest, 

 while less than a mile to the eastward the sun is shining, or, 

 at most, a few ^rops of rain are carried by the furious gale 

 which nearly always accompanies the downpour. So sharp is 

 this distinction between western forest and eastern grassland 

 from the north of the South Island to the forest of Southland 

 that hardly a single tree invades the grassland, but the forest 

 stands a dense, dark barrier with clean-cut margin, whence 



19. Of course certain species in these lists do not belong to the forest flora. 



