Cockayne. — Plants of Chatham Island. 270 



sides of the lamina are often much recurved or rolled back, 

 rendering the under-surface of the leaf concave. The epider- 

 mis has a much-thickened outer wall, and the cells are equal 

 in length to those of the palisade parenchyma, while their long 

 axis is at right angles to the surface of the leaf. Hymenanthera 

 chathamii a"'- has lanceolate leaves, which are thick and coria- 

 ceous, and the lamina is 8 cm. by 2'7 cm., more or less. They 

 are of a rather pale-green colour. The epidermis of the upper 

 surface is three-layered, the lateral walls of the two inner 

 layers being very thin. A stereome sheath surrounds the 

 vascular bundles, and adjacent to some of them is a colour- 

 less water-tissue. Coprosma chathamica has leaves rather 

 thinner in texture than most of the other forest trees, oblong 

 or obovate in shape and variable in size, the lamina often 

 being about 4 - 9 cm. by 2-3 cm. They are dark-green and shin- 

 ing on the upper surface, and very pale on the under-surface. 

 The small pits ('' Domatia ") common on the under-surface of 

 the leaf of Coprosmas, and first called attention to by Cheese- 

 man (7), at the junction of a vein with the midrib, are 

 very distinct. Mr. Hamilton has written about them more 

 recently (32), but has added nothing to our knowledge of 

 their function. The epidermis is two-layered, and a trans- 

 verse section of the leaf shows a layer of water- tissue 

 stretching from the epidermal cells to the vascular bundles 

 through the palisade parenchyma. Veronica gigantea has 

 narrow-lanceolate, quite sessile leaves, averaging probably 

 about 8 - 3cm. by l - 8cm. They are soft, bright-green in colour 

 on the upper surface, thicker in texture than any form of 

 V. salicifolia with which I am acquainted, and crowded to- 

 gether rather closely at the ends of the branches. Piper 

 excelsum is distinctly a hygrophyte. It has very thin dark- 

 green leaves, with their laminae 10-6 cm. long by 9-3 cm. 

 broad, and the apex drawn out to a fine point. 



With the exception of 0. traversii and Corokia macrocarpa , 

 the former having multitudes of white daisy-like flower-heads, 

 and the latter many small but bright-yellow flowers, the trees 

 of the lowland forest have very inconspicuous blooms. Their 

 fruits, on the contrary, are often large and showy. For ex- 

 ample, Corynocarpus laevigata has great clusters of very large 

 fruits, each measuring 4 cm. by 2 cm.; Myrsine chathamica 

 has the naked branches below the leaves covered with most 

 beautiful mauve-coloured drupes, which, according to Mr. 

 Cox, take fully a year to develope their brilliant colour. The 

 bare stems of Hymenanthera chathamica are similarly covered 

 with large white berries. Corokia macrocarpa is frequently 



* Diels's figure of the anatomy of the leaf of H. latifolia (16, p. 230) 

 shows almost identical structure with that of the Chatham Island plant. 



