Medical Officers of the Army of India.
67
The distribution of the 15 species confined to Asia varies somewhat in different
instances. This is more easily understood when the facts are tabulated—
TABLE IV.—Laccadive plants confined to Asia.
Extended to the Laccadives from
No. of
species. Per cent.
India, Burma, Malaya, Ceylon
.
.
.
.
•
.
.
9
1 1 ¼
India, Burma, Ceylon .
.
.
.
.
.
.
.
3
3¾
India, Burma
. . . . . . . .
1
1 ¼
India, Malaya
.
. . . . . . . . .
1
1 ¼
India alone
. . . . . . . . . .
1
1 ¼
TOTAL
.
15
18¾
The class of plants to appear first in the archipelago were those belonging
to the coast flora, since they could arrive almost as early as wind-conveyed
species, and would find the conditions offered by newly emerged islets favour-
able for their existence long before these became favourable for wind-dispersed
forms, while birds, and, as a consequence, bird-conveyed species, would be unlikely
to alight on the islands before the establishment on them of a sea-conveyed
flora inviting them to do so. A reference to TABLE I shows how completely this
theoretical conclusion is borne out by the present character of the flora ; inde-
pendently of those species whose appearance has been due to human agency, the
coast species—which the physical conditions are favourable for—are, as compar-
ed with the inland species, more numerous almost in the proportion of 3 : 1 ; as
compared with wind-introduced species alone—the introduction of whose seeds or
spores may have begun equally early, but for whose existence the conditions are
less favourable even now—more numerous in a proportion of over 4 : 1 ; at the
same time bird-conveyed species for which the conditions are not more unfavour-
able than they are for wind-conveyed species, but which have probably been later
of introduction—are less numerous than wind conveyed species.
While there is this more than general agreement with the results that a
consideration of the probable physical history of the islands would lead us to
expect, the numbers discussed are too small to render the statistics conclusive.
But the further evidence necessary is to be obtained by a comparison of the
list of plants already given with a list of the seeds and fruits picked up and a list
of the plants observed growing on an uninhabited island just beginning to receive
a flora such as Krakatau when visited in 1886 by Dr. Treub of Buitenzorg. 1 A l l
1 K R A K A T A U i s a v o l c a n i c i s l a n d i n t h e S t r a i t s o f S u n d a , t h e c r a t e r s o f w h i c h w e r e u n u s u a l l y a c t i v e
from May till October 1883, and which was in August (26th, 27th and 28th) of that year the scene of an
eruption of extraordinary violence that greatly altered the physiographical features of the island and com-
pletely destroyed the whole of its previously luxuriant vegetation. Dr. Treub visited the island in 1886 to
ascertain what species had during the interval reached the island and what light these might throw on the
processes of affloration. In this case the agency of man is completely eliminated, and only, those of the sea-
birds, or winds are at work. Dr. Treub's paper has been already referred to ; it is to be found in Ann. Jard.
B o t . B u i t e n z o r g , v i i , 2 1 3 .
K2