MARCH 
27th. 1934. 
59- 
NOTES ON CALADENIA LATIFOLIA, R.BR. 
By Harold Goldsack. 
la his Presidential Address before the Botanical Section of 
the Australian and New Zealand Association for the Advance¬ 
ment of Science, August. 1932, Dr. R. S. Rogers writes concern¬ 
ing the pollination of orchids as follows: “The numerous devices 
to secure the application of the pollen to the stigma are often 
very elaborate, indeed, in certain cases the)' may be regarded as 
almost human in their ingenuity. \\ henever the transfer is ef¬ 
fected bv insect agency, there is always payment for services, 
rendered. This generally takes the form of nectar or pollen, but 
sometimes the nature of the currency is obscure. Great resource 
is displayed bv the orchid in catering for the comfort and con¬ 
venience of its visitors. Guide lines and other directionary signs, 
platforms and adaptions of various kinds are all generously pro¬ 
vided for the needs of special insects. 1 he mechanism is as far 
as possible fool-proof and as remuneration only follows a success¬ 
ful transfer there is no incenti\e for unskilled operators to fre¬ 
quent these flowers. The adaptability of this highly specialised 
family is very surprising. Obsolete or superfluous structures dis¬ 
appear, and the mechanism wherewith to meet new or altered 
conditions is merely a modification of existing pacts,'' 
When we study the genus Caladenia we are very lorcibly 
impressed with our lack of knowledge concerning the payment 
which the insects, that visit the various species, receive. I p t<v 
the present time the pollination of two species is all that we 
know about the visits of insects to this large genus, which, it 
might be mentioned, contains about 75 species. 
The first purposeful visit to be described was that of a black 
wasp-like insect to Caladenia Barbaras sae Rcichb. fil. by Sargent 
in 1907. These insects were observed to suck a sweetened juice 
from the conspicuous central callus on the label turn, and while 
thus engaged performed the act of pollination for the flower. 
The next species to be observed during pollination was Caladenia 
dejovmis R.Br. This was recorded by Rogers in 'Trans. Royal 
Soc. S.A. for 1931. In this case the actual payment to the insect 
was not observed, owing to the structure of the flower which 
renders observation difficult, but it was suggested that the re¬ 
ward might be a sweetened drink from the large colourless basal 
cal 11 on the labellum. This orchid, though small, has a bright 
blue flower and adds to its attractiveness with a sweet though 
not very strong perfume. 
The larger species such as Caladenia dilata R.Br. and Cala¬ 
denia Patersonii R.Br., have little scent and show no signs of 
nectar; to our eves they seem to rely solely on their bizarre 
