282 Transactions. — Botany. 



The presence of the heath plant-formation seems to de- 

 pend upon the amount of water in the soil, and, as mentioned 

 above, upon the exposure of the station to wind, while, ac- 

 cording to the relative dryness of the substratum, certain 

 plants may be present or absent. Thus, the following occur 

 only on the driest ridges : Leucopogon richei, Cyathodes 

 robusta, Pimelea arenaria, Isolepis nodosa, Libertia ixioides, 

 var. In such a position L. ixioides at times almost con- 

 stitutes a subformation, forming, thanks to its power of 

 spreading by underground stems, very large patches. Its 

 xerophytic, coriaceous, vertical, iris-like leaves also help to 

 maintain the plant in its dry station. Growing in these 

 Libertia patches, but in very limited quantities, are Agrostis 

 cemula, Gnaphalium involucratum, Accena nova-zelandia,, and 

 a few stunted plants of Dracophyllum paludosum and Pteris 

 escuienta. In many places the heath consists of nothing but 

 Pteris escuienta, which often grows with great luxuriance, 

 and attains a height of 1*5 m. or more. Where the fern is 

 not so tall a number of other plants are found in association 

 with it. In such positions the following were noted : Epilo- 

 bium sp. (perhaps related to E. novce-zelandics), Lageno- 

 phora forsteri, Gnaphalium filicaule, Oreomyrrhis colensoi, 

 Gentiana pleurogynoides var. umbellata, Pratia arenaria, 

 Isolepis nodosa, Accena nova-zelandia, Hydrocotyle mos- 

 chata, Danthonia semi-annularis , Dichelachne crinita, Thely- 

 mitra lougifoiia, Microtis porrifulia, Luzula sp. Also plants 

 of Dracophyllum paludosum and Olearia semidentata are 

 occasionally present, a remnant of the original bog forma- 

 tion. 



The soil of this formation is usually peaty loam, varying 

 much in the amount of water it contains, but except on the 

 ridges mentioned before it is never really dry. Formerly 

 there was probably, as pointed out further on, only a limited 

 extent of heath, with bracken as the dominant plant, and 

 undoubtedly Phormium tenax would play a very important 

 part in the vegetation. A proof of this is afforded by Phor- 

 mium occurring in very large quantities in the hollow before 

 mentioned, where the peat had been burned, and the steep 

 sides of which prevent the entrance of grazing animals. 



Except on the southern tableland the heath formation is 

 found in all parts of the island ; indeed, so far as I can 

 judge, it occupies a larger area than any other formation. 

 On the large extent of flat land raised a little above sea- 

 level, marked " Kekerione " on the map (49), and intersected 

 here and there by puny watercourses, wherever the surface 

 sinks a little below the general level is boggy ground ; but 

 all the remainder, by far the greater part, is covered with 

 bracken, varying from a vegetation of almost pure Pteris 



