EFFECT OF SETTLEMENT UPON INDIGENOUS VEGETATION. 185 
bush growth, which at first sight might perhaps be taken for 
original vegetation, but which is composed of plants which have 
overrun the deserted sugar plantations. It is only in afew remote 
parts of the island that any original forest exists and in small 
streaks of broken ground bordering the watercourses.”* And 
again, ‘It is only in the highest part of the island of Madeira 
that anything is to be seen of the true indigenous vegetation. 
Below, cultivation has destroyed the native plants.” + 
We now arrive at the indirect injury caused by settlement. 
(a.) Indirect injury to the flora from forest clearing. 
The damage done to the indigenous plants by clearing does not 
stop with the mere killing of the forest trees. The plants beneath 
them having grown up under their shade, and being adapted for 
life under such conditions, suffer immediately when the shade is 
withdrawn. A good instance of this may often be seen when the 
rich brush country in Illawarra is cleared. In these forests the 
only undergrowth consists of saplings of the prevalent trees, and 
ferns of the following genera: Trichomanes, Hymenophyllum, 
Alsophila, Adiantum, Pteris, Lomaria, Blechnum, Asplenium, 
Polypodium, and on the tree trunks Platyceriwm. Immediately 
the land is cleared, the majority of these die off, the earliest to _ 
suffer being the first two genera ; and those which are not killed 
by exposure to the sun, merely keep alive, and make no headway. 
If the cleared land be let stand idle, other plants, both indigenous 
and introduced, suited for the new conditions, invade the space, 
and in a short time there is a new growth, partly consisting of 
the old plants, but chiefly of introduced plants and indigenous 
plants not previously found here. 
That a new indigenous flora sometimes springs up in cleared 
lands is well authenticated. Wallace says: “It is a known fact 
that when forests are destroyed, trees of a different kind usually 
occupy the ground.”{ Again, “Denmark has at present forests 
* Notes of a Naturalist on the Challenger, p. 11. 
+ Op. cit., p. 40. 
} Geographical Distribution of Plants, first edition, Vol. 1., p. 43. 
