106 Transactions. 



Autecology of Forest-plants. 



The trees are usually of irregular growth, with trunks in high forest 10 m. or 

 so before branching into a large rounded head. Plank buttresses are frequent. 

 Ficus columnaris and Acicalyptus Fullagari have trunks up to 1 m. or 1| m. 

 in diameter with large plank buttresses. In Hemycyclia australasica, and 

 Acronychia Baueri the bases of old trees show a tendency toward plank 

 buttresses, small ones f m. or so up the stem being the rule, and the roots 

 often run for some distance along the surface. 



Adventitious roots are developed in Metrosideros, Ficus, and Pandanus. 

 They are small in Metrosideros nervidosa, springing from the underside of 

 some of the branches and hanging freely down. In Ficus columnaris they 

 arise from the horizontal branches, and, growing downwards, take root on 

 reaching the ground, eventually forming columnar supports similar to the 

 main stem. This itself in most cases began in the same way as the Ficus 

 usually begins life — as an epiphyte. As with some other species of the 

 genus, Ficus columnaris habitually forms columnar roots, and, like the 

 famous banyan, single specimens may cover a considerable area of 

 ground. 



Pandanus Forsteri throws out obliquely downwards from all sides of 

 the stem cylindrical stilt-like roots which eventually replace the main stem. 

 This, when once formed, does not increase in size, and thus it is smallest at 

 the base and gradually thickens upwards. In old plants the lowest and 

 therefore oldest and smallest portion of the main stem is usually withered 

 and dead, the plant depending entirely on the stilt roots for support and 

 nourishment. 



Subepidermal aqueous tissue is developed in Ficus columnaris (really 

 a three-layered epidermis), Acicalyptus Fullagari, Lagunaria Pater soni, 

 Coprosma putida, Notelaea quadristaminea, Negria rhabdothamnoides, and 

 Metrosideros nervidosa. The mesophyll is not differentiated into palisade 

 and spongy parenchyma in Randia stipulosa and Drimys howeana. There 

 is a thick cuticle in Ficus columnaris, Acicalyptus Fullagari. Hemicyclia 

 australasica, Metrosideros nervidosa, and Baloghia lucida. It is thinner in 

 Cryptocarya triplinervis, Notelaea quadristaminea, Coprosma putida, Lagunaria 

 Patersoni, Rapanea platystigma, and Dracophyllum Fitzgeraldi. There is 

 a layer of sclerenchyma beneath the upper epidermis in Dracophyllum 

 Fitzgeraldi. 



2. Moss Forest. 



The summit of Mount Gower, which, as already mentioned, forms an 

 undulating plateau, is covered with dense scrub or low-forest vegetation, 

 which extends a little way down the steep sides of the mountain. The 

 scrub varies in height, and slightly in composition, according to exposure. 

 Where it is most sheltered, as in the ravines, its height is about 4 m. It is 

 composed of a mixture of small trees or shrubs, palms, and tree-ferns. 

 There is an undergrowth of low ferns and sedges, while the floor is for the 

 most part covered with mosses. Epiphytes cover almost every available 

 space on the larger plants. Clouds frequently envelop the mountain- 

 summit, and in consequence the vegetation is usually reeking with moisture. 

 One finds here, therefore, a luxuriance and wealth of plant-life unknown 

 on the drier habitats at lower altitudes. I am informed by Mr. R. S. Bell 

 that some moss forest occurs on the summit of Mount Lidgbird. 



Standing on a tree on the highest point of Mount Gower one may get 

 a bird's-eye view of the plateau. The upper surface of the scrub is compact 



