Oliver. — Vegetation of the Kermadec Islands. 147 



(c.) Pohutukaica (Metrosideros) Forest. — Mdrosideros villosa in tlie erup- 

 tion area is a slender tree, usually with, several stems springing fiom the same 

 root ; the lower branchlets are dead, and the foliage chiefly borne at the 

 top ; height, 8 m. ; circumference of stems, 18-46 cm. 



On the inner crater ridge the forest is composed almost exclusively of 

 Metrosideros saplings 8 m. tall, growing close together. The grourid is 

 quite bare of vegetation nearly everywhere, but dead leaves and sticks 

 are thickly strewn about. Where there is a break in the forest, Ageratum 

 conyzoides, Oplismenus undulatijolius, &c., are found. 



The gullies between this ridge and Mount Campbell are filled with ferns, 

 chieflv young Cyathea Milnei and Pteris comans. 



On the flat ground at the base of Moumoukai Coriaria sarmentosa, 

 Coprosma acntifolia, Myoporum ketum, and Cyathea Milnei occur with 

 Metrosideros villosa, while Cyelophorus serpens is occasionally present as an 

 epiphyte. The undergrowth when present contains Polystichum aristatum, 

 Pellcea falcata, and Nephrolepis cordifolia. 



5. Introduced Formations. 



I apply the term " introduced " to the three meadows occurring in 

 the Kermadec Islands because in each the principal plant is an imported 

 species. In all cases these meadows occupy ground cleared of its original 

 scrub or forest by man. The soil, unlike that of the " young " formations, 

 was at the time of the clearing of the forest in a fit state to receive new 

 plants, and the existence of these formations is, in my opinion, good evidence 

 of the superiority of plants of widespread occuiTence over indigenous plants 

 in a confined area where competition has not been keen. But climatic 

 conditions on Sunday Island favour the gTowth of forest, so that, though 

 the newcomers quickly take possession of the ground, they must eventually 

 retreat before the encroaching forest. With regard to ground occupied 

 by the young formations, it is in its nature so barren that indigenous species 

 of trees (Metrosideros villosa, Myoporun Icetum, Coriaria sarmentosa) grow 

 as fast as introduced plants ; hence the latter, suffering from the shade 

 of the former, have not a chance of monopolizing the ground. In any case, 

 if let alone forest will ultimately cover both areas, with introduced plants 

 as unimportant members only. 



(a.) Ageratum Meadotv. — Ageratum meadow occupies all the clearings 

 in the forest in Denham Bay. The chief plant is Ageratum conyzoides, which 

 covers the ground to a height of about | m. The leaves are hght green 

 or yellowish-green ; lilac-blue flowers are produced profusely throughout 

 the year. All other plants in this formation occur more or less sporadically. 

 The following are most commonly met with : Dryopteris parasitica, KyUinga 

 brevifolia, Carex lucida, Sida rhoinbifolia, Vinca rosea, and Anthoxanthutn 

 odoratum. 



(b.) Buffalo - grass (Stenotaphrum) Meadow. — Buffalo - grass meadow 

 occurs on the Terraces, on Low Flat and the adjoining crater-ridge, and in 

 one place on the east coast. It forms a dense impenetrable mass, |-2 m. 

 high, with an uneven surface. It has taken almost entire possession of the 

 ground, as only a few other plants struggle for a bare existence amongst it. 



So much do the culms of the buffalo-grass (Stenotaphrum glahrum) inter- 

 twine, and so dense is the resulting mass, that it is only with the greatest 

 <lifficulty that one can scramble^ over it, while walking through it is quite 

 impossible. It is shunned by every one who has been unfortunate enough 



