292 THE ORCHID REVIEW. [SEPTEMBER, 1913. 
POLLINATION OF DISA UNIFLORA. 
AN interesting article on the pollination of the brilliant scarlet Disa uniflora 
appeared in the Cape Times for April 5th last, which is here summarised. 
It appears that Mr. Harold Hamer has presented to the South African 
Museum Herbarium a specimen. of a ripe seed capsule, found in Window 
Gorge, and he states that many of the other flowers showed signs of a 
swollen ovary, which probably means that they have been pollinated and 
will eventually produce ripe fruits. This discovery opens anew a con- 
troversy on the pollination of this Disa. 
Roland Trimen, as early as 1863, opened the subject. He had 
examined a large number of Disa uniflora flowers, and in several cases 
found that one of the pollinia had been removed, but in no case saw a 
stigma with pollen grains adhering to it. He concluded that the remark- 
able brilliant colour of the flower is probably attractive to some day-flying 
hymenopterous or lepidopterous insect, and suggests that Disa uniflora 
offers nearly a parallel case to that described by Darwin, of the extremely 
imperfect fertilisation of Ophrys muscifera in England. 
In 1888 the late Dr. Bolus monographed the Cape Peninsula Orchids, 
and states that he had never seen a matured seed-vessel, nor been able to 
detect any insect employed in its pollination, and he thought that the 
insect effecting pollination had become extinct, and that the plant was 
propagated solely by means of tubers. In 1895 Dr. Marloth read a paper 
before the South African Philosophical Society, and mentioned that fully- 
developed fruits had been found by Prof. MacOwan, Mr. Kassner, Mr. 
Schlechter, Mr. Chas. Ross, and himself, and concluded that the Disa was 
pollinated by insects like other Orchids. As a further proof of this Dr. 
Marloth was fortunate in capturing a butterfly, Meneris Tulbaghia (the 
Mountain Pride) in the vicinity of a cluster of Disas, which had a pollinium 
attached to one of its legs. About two years ago Mr. Phillips saw one of 
these butterflies with a pollinium adhering to it. These facts go to prove 
that Disa uniflora, though chiefly propagated vegetatively, is also some- 
times fertilised and produces seeds. 
This is the first season this Disa has been protected from being plucked 
at all, which will account for its profusion of bloom on Table Mountain 
this year, and will probably mean that a larger percentage of flowers, 
especially those growing on exposed cliffs, will become pollinated and 
produce seed, than when wholesale picking was allowed as in former years. 
Vegetative reproduction by means of tubers may be the chief method of 
propagation in this plant, as pointed out by Dr. Bolus and Dr. Marloth, 
but this only means that the Disa will be preserved in the few localised 
areas it is now found in. It is only when it produces seed, which are 
