Cockayne. — Plants of Chatham Island. 293 



on its surface. Everywhere the floor of the forest is very- 

 uneven, and is covered with many dead and decaying steins 

 of trees or tree ferns and mounds of humus. Every 

 tree-trunk, tree-fern stem, and dead tree is covered with 

 multitudes of filmy ferns. The lowest layer of vegetation 

 consists of young tree ferns, especially of Dicksonia squar- 

 rosa and other ferns such as were enumerated hefore for the 

 lowland forest. Here and there at certain seasons of the 

 year the small red fruit-body of a fungus is abundant. The 

 next layer of vegetation is composed of the fully grown tree 

 ferns Dicksonia squarrosa and Dicksonia antarctica. Many of 

 these latter are more than 4-5 in. in height, and their huge 

 spreading fronds serve to intensify the shade of the forest and 

 to conserve the moisture of the atmosphere. This under- 

 growth of tree ferns is often so dense that their stems 

 almost touch each other. Epiphytic on the tree-fern stems 

 are Trichomanes venosum, Hymenophyllum multifidum, H. di- 

 latatum, Trichomanes rcniforme, Aspidium capense, Asplenium 

 lucidum, and various seedling trees. The filmy ferns are 

 often so thick that they completely hide the trunk of tree or 

 fern on which they grow. In many places the ground also is 

 covered with a thick carpet of these delicate plants. In deep 

 forest-clad gullies, where a stream at the bottom and the wet 

 ground constantly discharge water-vapour into the air of the 

 forest, where it is confined by the double shade of tree-tops 

 and fern -fronds, it can readily be seen that such a gully is a 

 station of the most intensely hygrophytic character, espe- 

 cially if the climate of Chatham Island, with its many 

 morning mists and light showers, be borne in mind. In 

 such a place, too, the wind, that factor nearly always to 

 be reckoned with when considering New T Zealand plant 

 forms or distribution, can have but little drying influence. 

 In such a station Trichomanes reniforme, the kidney fern, 

 often grows with extreme luxuriance, the ground, fallen trees, 

 tree-trunks, and tree-fern stems being covered with its great 

 almost round green leaves, the younger ones of which are 

 much brighter green and so thin as to be almost trans- 

 parent. In many places this fern receives a considerable 

 amount of sunlight ; but this can do no damage, since the 

 air which surrounds the fronds is always sufficiently moist. 



It has already been pointed out what an excellent station 

 for the welfare of seedling plants tree-fern stems offer — a 

 very much better one, indeed, than the crowded and some- 

 times not too well-drained forest floor. Such seedling trees 

 very frequently reach a large size, especially Dracophyllum 

 arboreum, the roots of which plant, penetrating deeply into the 

 soft mat of aerial roots of the fern, finally reach the ground. 

 The plant then grows with redoubled vigour, and in the 



