FEETILIZATION IN PLANTS. 
429 
are attached by their caudicles to a single visid disc^ which^ in 
this instance^ is saddle-shaped (fig. 7). Another modification 
of the mode of fertilization consequently takes place. If the 
proboscis of a moth^ or a bristle, be thrust into the nectary, 
the pouch is depressed, and the saddle-shaped disc at- 
taches itself to the object introduced ; as soon as this object, 
with the adhering pollinia, is removed, by a rapid movement, 
consequent on drying, the flaps of the saddle curl around, and 
tightly embrace the object, so that in nine seconds it becomes 
hrmly secured. As soon as this is accomplished, the pollinia, 
which, by the by, have necessarily diverged from each other 
in the movement, sweep downwards and forwards through 
nearly ninety degrees, as in the former instance. In this posi- 
tion the two ends of the pollinia will be found to have acquired 
such an adjustment that one of the pollen-masses will strike 
the surface of the stigma on one side at the same moment 
that the other pollen-mass touches the surface of the stigma 
on the other side of the rostellum, and the flower is completely 
fertilized. 
In reference to this species Mr. Darwin remarks : — ■ 
As in no other plant, or indeed in hardly any animal, can adaptations of 
one part to another, and of the whole to other organized beings widely remote 
in the scale of nature, be named more perfect than those presented by this 
orchis, it may be worth while briefly to sum them up. As the flowers are 
visited both by day and night-flying Lepidoptera, I do not think that it is 
fanciful to believe that the bright purple tint attracts the day-fliers, and the 
strong foxy odour the night -fliers. The upper sepal and two upper petals 
form a hood protecting the anther and stigmatic surfaces from the weather. 
The labellum is developed into a long nectary in order to attract Lepidoptera, 
and we shall presently give reasons for suspecting that the nectar is pur- 
j)osely so lodged that it can . be sucked only slowly in order to give time for 
the curious chemical quality of the viscid matter on the under side of the 
saddle setting hard and dry. He who will insert a flne and flexible bristle 
into the expanded mouth of the sloping ridges on the labellum will not doubt 
that they serve as guides, and that they effectually prevent the bristle or 
proboscis from being inserted obliquely into the nectary. This circumstance 
is of manifest importance ; for, if the proboscis were inserted obliquely, the 
saddle-formed disc would become attached obliquely, and, after the com- 
pounded movement of the pollinia, they could not strike the two lateral 
stigmatic surfaces. 
Then we have the rostellum partially closing the mouth of the nectary, 
like a trap placed in a run for game ; and the trap so complete and perfect, 
with its symmetrical lines of rupture forming the saddle-shaped disc above, 
and the lip of the pouch below ; and, lastly, this lip so easily depressed that 
the proboscis of a moth could hardly fail to uncover the viscid disc and 
adhere to it. But if this did fail to occur, the elastic lip would rise again 
and re-cover and keep damp the viscid siuTace. We see the viscid matter 
