418 Transactions. 



nial cells occurring at the hinges a, a, are very large, with the 

 long axis vertical to the surface, some wedge-shaped ; their 

 outer walls are just slightly convex. Above the masses of 

 stereom tissue which occur at regular intervals on the upper 

 surface the epidermal cells are much smaller and flattened, 

 and the walls also do not project. It is on this upper surface, 

 which is also the inner surface when the leaf folds over, that 

 the stomata (st.) occur, partially protected by the papilla-. 

 Each guard-cell is accompanied by a subsidiary cell (sb.), which 

 assists in opening and closing the stoma (fig. 296). The lower 

 epidermis is composed of very thick-walled cells, with cuti- 

 cularized walls, generally cubical in shape, those beneath the 

 masses of the stereom tissue being much smaller, but still 

 cubical. Stereom (sm.) occurs in various parts of the leaf as 

 strengthening tissue against the effects of the wind. It is 

 found above and below each vascular bundle (v.b.). It forms 

 the little ridge projecting above the main vascular bundle on 

 the upper or inner side of the leaf (sm 1 ), and also a larger mass 

 of it forms the keel-like projection on the lower surface (sm.). 

 At a and a on either side of the central mass of tissue the 

 tissue between the large upper epidermal cells, which probably 

 act as hinges, and the lower epidermal cells is made up 

 of a mass of thick- walled colourless cells (col.). The rest of 

 the leaf consists of chlorenchyma (chlor.), small rounded cells 

 densely filled with protoplasm. A well-defined very thick- 

 walled endodermis surrounds each vascular bundle (fig. 29c). 

 The xylem (xy.) of the bundle shows well-developed and thick- 

 walled xylem vessels on the upper surface. 



List of Literature consulted. 



1847. Hooker, Sir J. D. : "Flora Antarctica," vols, i and i : 



London. 

 1852. Hombron and Jacquinot : " Voyage au Pole Sud : Bo- 



tanique." Paris. 

 1867. Hooker, Sir J. D. : " Handbook of the New Zealand 



Flora." London. 

 1881. Kirk, T. : " Notes on Plants from Campbell Islands." 



Trans. N.Z. Inst., vol. xiv, p. 387. 



1883. Scott, J. H. : " Macquarie Islands." Trans. N.Z. Inst., 

 vol. xv, p. 484. 



1884. Buchanan, J. : " Campbell Island and its Flora." 

 Trans. N.Z. Inst., vol. xvi, p. 398. 



1891. Chapman, F. R. : "The Outlying Islands south of New- 

 Zealand." Trans. N.Z. Inst., vol. xxxiii, p. 491. 

 1891. Kirk, T. : " On the Botany of the Antarctic Islands." 



