I wrote yesterday to thank you for the Epipactis. For the chance of your liking to look at what I have found: take a recently opened flower, drag gently up the stigmatic surface almost any object (the side of a hooked needle), and you will find the cap of the hemispherical rostellum comes off with a touch, and being viscid on under-surface, clings to needle, and as pollen-masses are already attached to the back of rostellum, the needle drags out much pollen. But to do this, the curiously projecting and fleshy summits of anther-cases must at some time be pushed back slightly. Now when an insect's head gets into the flower, when the flap of the labellum has closed by its elasticity, the insect would naturally creep out by the back-side of the flower. And mark when the insect flies to another flower with the pollen-masses adhering to it, if the flap of labellum did not easily open and allow free ingress to the insect, it would surely rub off the pollen on the upper petals, and so not leave it on stigma. It is to know whether I have rightly interpreted the structure of this whole flower that I am so curious to see how insects act. Small insects, I daresay, would crawl in and out and do nothing. I hope that I shall not have wearied you with these details. If you would like to see a pretty and curious little sight, look to Orchis pyramidalis, and you will see that the sticky glands are congenitally united into a saddle-shaped organ. Remove this under microscope by pincers applied to foot-stalk of pollen-mass, and look quickly at the spontaneous movement of the saddle-shaped organs and see how beautifully adapted to seize proboscis of moth. LETTER 597. TO J.D. HOOKER December 4th [1860]. Many thanks about Apocynum and Meyen.