38 THE ORCHID REVIEW. [FEBRUARY, 1922 
TWISTING OF THE OVARY. 
HE interesting article in our last issue concerning the twisting of the 
C ovary recalls Darwin’s statement that ‘‘in many Orchids the ovarium, 
and sometimes the foot-stalk, becomes for a period twisted, causing the 
labellum to assume the position of a lower petal, so that insects can easily 
visit the flower; but from slow changes in the form or position of the petals, 
or from new sorts of insects visiting the flowers, it might be advantageous 
to the plant that the labellum should resume its normal position on the 
upper side of the flower, as is actually the case with Malaxis paludosa.” 
“This change, it is obvious, might be simply effected by the continued 
selection of varieties which had their ovaria less and less twisted ; but if the 
plant only afforded varieties with the ovarium more twisted, the same end 
could be attained by the selection of such variations, until the flower was 
turned completely round on its axis. This seems to have actually occurred 
with Malaxis paludosa, for the labellum has acquired its present upward 
position by the ovarium being twisted twice as much as is usual.’— 
Fertilisation of Orchids. 
A similar case of the ovary having a whole turn or twist, thus bringing the 
labellum again to an upright position, is given by H. Bolus in reference to 
Disa elegans. He remarks, “ this species is closely allied to D. Bodkini. 
Without doubt it belongs to the same group, which, before I knew this 
species, I called Orthocarpa, because of the untwisted ovary, and the 
resulting posticous lip. But in the present species the same result, or nearly 
the same, is produced in a curiously different way. The ovary has here 
nearly a whole turn or twist (in most Disz it has a half-twist) and this, of 
course, brings the lip also into a nearly posticous position as regards the 
axis of growth. This is the only instance of the kind I have ever seen in 
the genus.” —Orchids of South Africa. 
