ORCHIDACE®. 89 
sweep through about 90 degrees always in one direction, viz. towards the apex of the 
proboscis or pencil in the course on an average of thirty seconds. Now after this 
movement and the interval of time which would allow the insect to fly to another 
flower, it will be seen that if the pencil be inserted into the nectary, the thick end of 
the pollen-bag will exactly strike the stigmatic surface. Here again comes into play 
another pretty adaptation, long ago noticed by Robert Brown. The stigma is very 
viscid, but not so viscid as when touched to pull the whole pollen-bag off the insect’s 
_ head or off the pencil, yet sufficiently viscid to break the elastic threads by which the 
packets of pollen-grains are tied together and eave some of them on the stigma. 
Hence a pollen-bag attached to an insect or to the pencil can be applied to many 
stigmas and will fertilise all. I have seen the pollen-bag of Orchis pyramidalis 
adhering to the proboscis of a moth, with the stump-like caudicle alone left, all the 
packets of pollen having been left glued to the stigmas of the flowers successively 
visited. One or two little points must still be noticed. The balls of viscid matter 
within the pouch-formed rostellum are surrounded with fluid; and this is very impor- 
tant, for, as already mentioned, the viscid matter sets hard when exposed to the air 
for a very short time. I have pulled the balls out of their pouches, and have found 
that in a few minutes they entirely lost their power of adhesion. Again, the little 
dises of membrane, the movement of which as causing the movement of the pollen- 
bags is so absolutely indispensable for the fertilisation of the flower, lie at the upper 
and back surface of the rostellum, and are closely enfolded and thus kept damp 
within the bases of the anther-cells ; and this is very necessary, as an exposure of about 
thirty seconds causes the movement of depression to take place; but as long as the 
disc is kept damp the pollen-bags remain ready for action whenever removed by an 
insect. Lastly, as I have shown, the pouch after having been depressed springs up to its 
former position, and this is of great service; for, if this action did not take place, and 
an insect after depressing the lip failed to remove either viscid ball, or if it removed 
one alone, in the first case both, and in the second case one of the viscid balls would 
be left exposed to the air. Consequently they would quickly lose all adhesiveness, 
and the pollen would be rendered absolutely useless. That insects often remove one 
' alone of the two pollen-bags or pollinia at a time in many kinds of orchis is certain; 
‘itis even probable that they generally remove only one at a time, for the lower and 
| older flowers almost always have both pollen-bags removed, and the younger flowers 
' close beneath the buds, which will have been seldomer visited, have frequently only 
one pollinium removed. In a spike of Orchis maculata I found as many as ten flowers, 
| chiefly the upper ones, which had onty one pollinium removed ; the other pollinium 
being in place, with the lip of the rostellum well closed wp, and all the mechanism 
perfect for its subsequent removal by some insect.’”’ The nectary of Aceras anthropo- 
phora, our present species, is very short. 
The British species of Orchis are mostly red or lilac in colour, sometimes white or 
green, and often beautifully mottled. With the exception of the green ones, all seem 
capable of the albino condition, and there are few that do not exhale perfume, espe- 
cially in the evening; many kinds are, however, very capricious in this respect. 
They grow in woods, meadows, and pastures, in marshes, upon hills, and on grassy 
banks exposed to the splash of the sea; the insectiform species, however, are almost, 
entirely confined to chalk and limestone. For the microscope they furnish, in all 
their parts, very beautiful objects. The green flowers of the species mentioned above 
present the figure of a little man “swinging as if some great ogre held him by the 
hair of his head.”’ 
VOL, IX. N 
