% 56 The Vegetation of the Sea-coast. 
Chapter II. The Biology of the Coastal Plants. 4 
1. Growth-Forms. 
a. Trees. 
The coastal trees number 28; all are evergreen. Excepting 3 species‘), 
none exceed 9 m in height, 6 m or less being a common stature. The tree- 
form is generally unsuited to coastal conditions, consequently, in exposed 
stations, no fewer than 24 of the trees do not develope a distinct trunk-but 
blossom and ripen abundant fruit as shrubs merely. a 
The following are the growth-forms and number .of species to each: 
Canopy-tree ıı; bushy-tree 9°); tree-composite 4; araliad 3; and bamboo-like 1, 
Paratrophis Smithit when a shrub is of the divaricating-form’). = 
The tree-trunks, as a rule, are slender and erect, but in the latter respect z 
some are extremely plastic, e. g. the southern tree-composites, which in response 
to the frequent gales, develope more or less horizontal trunks whose spread : 
may far exceed the vertical height of the tree. Metrosideros tomentosa, t00, 
growing out of a cliff-face, extends horizontally, but, when its station is ordinary 
level ground, the trunk is erect, though frequently very short indeed, in which 
case numerous erect branches function as trunks and the form is that cf a 
gigantic shrub. Macropiper excelsum has frequentiy a much-reduced trunk, 
but its stems are in a category by themselves, being straight, slender, blackish- 
purple when young, brownish purple when mature, marked at distant t intervals 
with leaf-scars and of a bamboo-like appearance. 2 
The roots of the coastal trees, like those of New Zealand trees in Zeneral, er 
un extend semi-horizontally rather than vertically downwards. Frequently 
are of great length. The root-systems of the mangrove [Avicennia 
| eat) and of Metrosideros tomentosa have been described in the last 
chapter. 
The leaves of all the species are Bra and, wich 3 exceptions, siurol 
"those of 7 are very large (over 20 cm long), but the remainder have leaves 
of medium size (5—-ıo cm long), except in a few species where they are smaller. 
Regarding texture 20 species have coriaceous leaves (6 thick), 2 rather fleshy 
and 6 quite thin. As for r hairiness the ee of = are ng and of 13 : 
; ae 8). 
un 
5. Shrubs. ae En 
he ad ruhe number 40 species, 21 of which are ie | 
19 1 seraphytes Seenl, of the Eee here dealt ‚wih: see with. some | 
nı) ee laevigatus, Mitresiierör tomentosa, Sw N were. | 5 
2) By the term “bushy-tree” is i  meant a low tree N short trunk ‚more or less 
