SUCCULENCE IN COASTAL PLANTS. 29 
frequently drapes the coastal ‘cliffs with its succulent reddish or pale- 
green leaves, and bears rather large rose-coloured or white flowers, 
according usually to the colour of the leaf, is a pleasing and familiar 
example. This species must not be confused with the Hottentot 
fig (M. edule), a native of South Africa, now naturalized on many 
sandhills, but which possesses leaves still “fatter”? than those of 
its indigenous sister, and bears larger and yellow-coloured flowers. 
Other common coastal succulents are the leafless Australian glass- 
wort (Salicornia australis) (fig. 14), a stem-succulent common in salt- 
meadows and on rocks close to the sea, and the sea-blite (Suaeda 
maritima), a leaf-succulent, usually growing in rather wetter ground 
than the glasswort and not nearly such a common plant. 
Succulence has been shown experimentally to be brought about 
by excess of salt in the soil, and certain plants to which salt is not 
a deadly poison can be made artificially succulent. Some of the 
introduced plants of this country, as, for example, the spotted catchfly 
(Stlene anglica var. quinquevulnera), acquire much fatter leaves when 
growing near the sea than when growing inland. 
The amount of succulence in coastal plants must not be over- 
estimated. The great majority are not succulent at all; but, then, 
they are usually not exposed to much salt. Even certain salt- 
meadow and salt-swamp plants are not succulent. Drought, in 
general, is combated in many foreign plants by means of succu- 
lence. Thus there are the numerous species of the succulent Cactus 
family—e.g., in Mexico—and the host of South African succulents 
belonging to various families. New Zealand, as will be seen, has 
also its succulents of dry stations in the subalpine and alpine belts. 
With regard to the growth-forms of the coastal plants, they fall 
into the familiar categories of trees, shrubs, lianes, herbs and semi- 
woody plants, and water-plants. The trees number about 28. 
Excepting the karaka (Corynocarpus laevigata) and the pohutukawa 
(Metrosideros tomentosa), the other trees rarely exceed 20 feet in 
height. But the tree form is unsuited to coastal conditions, and 
about 24 of the trees frequently do not develop a distinct trunk, 
but as shrubs bear abundant flowers and fruit. Even the pohutu- 
kawa, which attains a height of 70 feet or more in the forest, on 
Rangitoto Island blossoms freely when only a foot or so in height. 
In many cases the leaves of the coastal trees are more or less 
leathery or thick, as well might be expected. 
