Ridley . — On the Dispersal of Seeds by Wind . 361 
the parent, and from their occurrence in remote islands. Among the 
flowering plants we have the Orchids, Apostasia, and several species of 
Neuwiedia and Balanophora , all of which have very light seed which can be 
drifted away by the wind. 
The distance of the flight of Orchid seeds is probably, occasionally 
at least, very considerable, but I have but little direct information on this. 
Some epiphytic species were put in a Fiats Benjamina in a very open 
position — Cymbidium , a new species, and C. Finlay sonianum, and an Agrosto - 
phyllum. They fruited, and seeds of C. Fhilaysonianum flew southwards 
and grew on Arenga trees at a distance of 30 yards, Agrostophyllum 90 
yards ; the other Cymbidium 60 yards, northwards. Dendrobium pandaneti , 
which I planted on a Sago palm at one end of the garden, was found on 
some other Sagos nearly a mile away ; but I am not quite certain that the 
plants descended from the ones I first brought to the garden. The plant 
only grows on stems of Sagus, Pandanus , and Cocos . One curious thing 
about these epiphytic Orchids is, that the seed flying from a tree does not 
usually rest on the side of the tree facing the original plant, but on the 
further side, as if round the tree there was an eddy of wind which carried 
it there. I have seen the same thing in Psilotum complanatum , the spores 
of which must have flown from a plant in the plant-house, upwards and 
south-westwards, and lit on the trunk of a Date-palm 100 yards away. 
Very few of the numerous Orchids cultivated in the Botanic Gardens 
have, however, reproduced themselves on the garden trees. 
Orchids are not at all common as a rule in small islands. There were 
none in Fernando de Noronha. In Christmas Island, ten species are 
recorded ; three are endemic, two species of Phreatia, a genus Indo-Malayan 
and Pacific, and a Saccolabium ; of the others, Sarcochilus carinatifolia 
occurs also on Pulau Aur, a small island off the east coast of the Malay 
Peninsula. Dendrobium crumenatum ranges very widely over the Malay 
archipelago, and I have seen quite fresh, green-looking plants of it floating 
in the sea on the way to Christmas Island. The other Dendrobium is 
allied to a Javanese species. I have also found there a Javanese species of 
Thelasis. Of terrestrial Orchids there is a Corymbis allied to, though 
distinct from, C. veratrifolia , a plant of which hardly distinct forms occur 
from Africa to Java ; a Zeuxine and Didymoplexis pallens , a saprophytic 
plant ranging from the Himalayas to Java. This plant has a rather special 
modification for wind-dispersal, after fertilization. It is self-fertilized and 
the pedicels of the fruit elongate so as to be actually longer than the stem, 
and elevate the capsule well above the rotten leaves and the low ferns 
among which it grows. Carysanthes , also a widely distributed Orchid, has 
the same modification. 
As a rule terrestrial Orchids are more widely distributed than epiphytic 
ones, and saprophytic species are remarkably widely distributed. Con- 
