Betts. — Avtecology of Plants of Peridotite Belt, Nelson. 231 



The vegetation of the Mineral Belt presents a striking contrast with 

 that of the neighbouring land-surface, which is clothed with luxuriant 

 forests of southern-beech {Nothofagus spp.). On the Mineral Belt there are 

 three principal plant-associations :- 



1. Shrubland. — This is usually found near the margin of the Belt, and 

 is composed of many species that are found in the adjacent forests, but on 

 the Belt they are much dwarfed — e.g., Griselinia littoralis is usually a 

 tree 10-16 metres high, but in the shrub formation on the Mineral Belt it is 

 reduced to a woody shrub 3— 2 metres high; Nothofagus fusca, a forest-tree, 

 is represented by small trees 2-3 metres high. In addition to these dwarfed 

 representatives of the neighbouring forests there are in this association a 

 number of shrubs which are not reduced. Such plants are Cassinia Vau- 

 villiersii var.. Coprosma propinqua, Dracophyllum longifoliumvax., and Lepto- 

 spermum scoparium var. In this association there are a number of small 

 herbs — e.g., Glaytonia australasica, Colobanthus quitensis, and Epilobium 

 pedunculate var. 



2. Open Scrubland. —In this association the most characteristic plants 

 are Cassinia Vauvilliersii var., Dracophyllum rosmarinifolium, Exocarpus 

 Bidwillii. Hymenanthera dentata var. alpina, Veronica, buxifolia var., V. 

 Menziesii var., V.pinguifolia^.), Pimelea Suteri, and Muehlenbeckia axillaris. 

 Among the herbs to be found in this association are Myosotis Monroi, 

 Notothlaspi australe, Gentiana corymbifera, Anisotome aromatica, and A. 

 filifolium. 



3. Tussock Grassland. — The' dominant plant is Danthonia Raoulii var. ; 

 sub-dominant are Phormium Coohianum and Astelia montana var. 



It is proposed to describe the anatomy of a number of the plants of the 

 Mineral Belt in a series of short papers, and then the results obtained from 

 these investigations will be considered. 



In addition to the anatomy of the leaf and of the stem of the different 

 species, a brief description of the growth-form of the plant is given. In those 

 cases where the usual form of the species is found on the Mineral Belt this 

 description is quoted from Cheeseman's Manual of the New Zealand Flora 

 (1906). Where the species is modified in form, a description of the usual 

 type is quoted, and then that of the plant as it is found on the Mineral 

 Belt is given. 



1. Nothofagus fusca Oerst. 



Usual Growth-form. '' A noble forest-tree 60-100 ft. high ; trunk 4-8 ft. 

 diam. ; bark dark-brown or black in old plants, deeply furrowed, smooth 

 and greyish- white on young trees ; branchlets and petioles pubescent. 

 Leaves evergreen, petiolate, f-1^ in. long, broadly ovate or ovate-oblong, 

 obtuse or rarely acute, cuneate at the base, rather thin but firm, pubescent 

 above and glandular beneath when young, glabrous when old, deeply and 

 sharply serrate, veins conspicuous; stipules linear-oblong, caducous."' 



Mineral Belt Growth-form. — A small tree 6-8 ft. high, with leaves |-f in. 

 long. 



Anatomy. 



Leaf.- The upper epidermis consists of small cells, more or less oval in 

 transverse section. The cell-walls are thin, except the external walls, which 

 are slightly thickened and also cuticularized. Some of the epidermal cells, 

 in the vicinity of the vascular bundles, are produced into long unicellular 

 hairs which have thin, slightly cutinized walls. There are no stomates on 

 the upper surface. 



The lower epidermal cells are small, oval, and thin-walled, the external 

 walls being slightly thickened. A thin cuticle is present. Stomates are 



