24 



caespitosa excepted) though extending from the north of the 

 North Island to Stewart Island are not by any means on an 

 equality in the power of extending their area, in the variety of 

 stations which they occupy, or in the actual distance they have 

 travelled. The extremely plastic L. scoparium easily comes 

 first both for vertical range and the number of associations to 

 which it belongs, while the Dacrydium is limited to lowland and 

 montane forest or occasionally lower subalpine scrub (Stewart 

 Island) and the Scirpus to unstable dunes. The length of 

 time it must have taken the latter to pass from dune to acme 

 must have been comparatively short to that required by a species 

 of equal latitudinal range, but which, in addition, is a member 

 of the lowland and high-mountain floras and belongs to several 

 plant-associations demanding special adaptations. Between 

 continuity and extreme discontinuity of distribution there is 

 every degree of transition. Each species has its northern, 

 southern, eastern, western and altitudinal limits. Taking the 

 517 purely lowland species, according to statistics I prepared 

 nearly seven years ago, but have not verified since, 249 occur in 

 all the mainland Botanical Provinces, but only 102 of these 

 extend to Stewart Island. A number of wide-spread species 

 have their northern limit in the South Auckland Botanical Dis- 

 trict, a rather remarkable fact when the capabilities for dispersal 

 of some of them are considered. Amongst such are various 

 ferns and lycopods (e.g., Hymenophyllum pulcherrimum, H. 

 unilaterale, Blechnum penna marina, Polystichum vestitum, 

 Lycopodium varium, L. fastigiatum and L. scariosum) but 

 notwithstanding their capacity for spreading by means of spores, 

 it must be pointed out that these are generally mountain 

 species or they appear to "prefer" more or less subantarctic 

 conditions. So, too, with most of the spermaphytes of the same 

 category, e.g., Phyllocladus alpinus, Enargea parviflora, Cordy- 

 line indivisa, Nothofagus Menziesii, Nothopanax simplex and 

 Coprosma foetidissima. 



Coming now to some cases of isolation, or extremely re- 

 stricted distribution, the following may be noted : Lycopodium 

 Drummondii occurs only in one station, a bog near Kaitaia 

 (North Auckland). This is also indigenous in Australia and 

 when the number of suitable stations for its occupation are 

 considered, and its power of far-dispersal by means of spores, 

 its isolation is remarkable. For some reason or other it is 

 most likely dying out. Logania depressa grows to the south- 

 west of the Kaimanawa Mountains. Evidently it is extremely 

 rare as it "has not been collected since its original discovery 

 by Colenso more than sixty years ago. It apparently has no 

 close New Zealand relatives, so it may be looked upon as dying 

 out. Veronica Astoni is confined to the Tararua Mountains 

 where it is abundant. As this species is closely related to the 

 more widely spread V. tetragona of the Volcanic Plateau, Kai- 

 manawa and Ruahine Mountains, it must be considered of recent 

 origin. Coprosma Buchanani occurs only in a few places on 

 the shores of Cook Strait. Appaiently it has no near relatives, 



