THE POLLINATION OF SATYRIUM BICALLOSUM, 
THUNB. 
By S. GARSIDE. 
As comparatively few observations have yet been made upon the pollina- 
tion of South African orchids, the following account shoidd be of interest to 
those who are in a position to make further and much needed contributions 
to the subject. In the literature I have consulted, I have found no record of 
an insect having been seen to enter an orchid flower, and remove the pollinia 
from any South African orchid. Considering that many of the very numerous 
species of orchids which occur in the south-western region of South Africa 
are very common, this lack of information is somewhat remarkable. The 
possibility that many of the highly scented greenish orchids might be polli nated 
by night-flying insects might account for our scant knowledge of these. How- 
ever, observation of such a brightly coloured orchid as the scarlet Satyrium 
coriifolium, Sw., a species with both attractive colour and abundant nectar, 
shows that the visits of diurnal insects are by no means frequent. An examina- 
tion of the anther of this species usually gives evidence of insect visits, as 
the pollinia are frequently removed from the lower and older flowers in a spike. 
As this paper will indicate, cross-pollination may, in certain cases, occur only 
during a very few hours in the day, so that a patient watch would have to be 
kept before the pollinating insect would be discovered. 
For a few South African orchids, we already have several scattered observa- 
tions, in the nature of records of the capture or observation of insects carrying 
distinctive pollinia of known origin. The observations of several botanists have 
also proved that for several species, the pollinia are quite regularly removed, 
but the full story of the method of cross-pollination has not, so far, been 
available for a single South African orchid. 
As the literature relating to pollination is very scanty, the results so far 
obtained can be briefly reviewed here. 
Trimen 1 says that in Disa grandiflora ( D . uniflora) insect visits are rare. 
The brilliant colour indicates that day-flying lepidopterous or hymenopterous 
insects are the visitors. He also notes that the pollinia are very infrequently 
removed. Marloth 2 records the capture of a butterfly, Meneris tulbaghia, with 
a pollinium of Disa grayidiflora attached to its body. A figure of the insect, 
with the pollinium attached to the proboscis is given 3 . 
1 Trimen, 1864. 2 Marloth, 1895. 3 Id. 1915, Plate 59, Fig. 12. 
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