144 
WILLIS AND GARDINER : BOTANY 
and must be of importance in distributing these, and pro- 
bably other species, among the islands. 
Transport of Seeds, &c., by Wind Agency. 
On land and for short distances,* this is one of the most 
important of transport agencies, but very little evidence has 
as yet been collected to show that it is the means of carrying 
many seeds or plants across wide stretches of sea. Looking 
through the lists of plants above, the only fairly certain 
cases of wind transport are those of the spores of the ferns 
and Psiiotum, including the following species : — 
(Asplénium æquabile) 
( longissimum) 
( falcatum) 
Nephrolepis exaltata 
( tuberosa) 
( cordifolia) 
Thamnopteris Nidus 
Nephrodium molle 
( unitum) 
(Pteris marginata) 
Psiiotum triquetrum 
Of these, five, one of which is an endemic species, are 
confined to Diego Garcia, one to Minikoi, one to the Eastern 
Laccadives, and the others are fairly widely scattered among 
the islands. We may thus conclude that there is no distance 
by which any of these islands are separated from one another 
or from the mainland or other islands, which is too great for 
the transport of cryptogamie spores by wind. It must be 
remembered that the soil and climate of most of the islands 
are not highly favourable to cryptogams. Treub, in his 
interesting paper on the new fiora of Krakatoa, has shown 
how the ferns are about the first vegetation to appear, and 
has drawn from his observations the conclusion that in the 
colonization of distant oceanic islands, other than mere 
banks or small reefs, with plants, the ferns must take a great 
part, and form a large part of the vegetation, conclusions 
borne out by the actual composition of the floras of Juan 
Fernandez and Ascension. Passing on to the more proble- 
matic cases of wind transport, we have the case of the two 
* Cf. Willis and Burkill : The Flora of the Pollard Willows near Cam- 
bridge, Proc. Camb. Phil. Soc., 1893. 
