Since I have had an opportunity of perusing your work on orchid fertilisation, my attention has been particularly directed to the curiously constructed floral organs of Acropera. I unfortunately have as yet had only a few flowers for experimental enquiry, otherwise my remarks might have been clearer and more satisfactory. Such as they are, however, I respectfully lay [them] before you, with a full assurance of their veracity, and I sincerely trust that as such you will receive them. Your observations seem to have been chiefly directed to the A. luteola, mine to the A. Loddigesii, which, however, as you remark, is in a very similar constructural condition with the former; having the same narrow stigmatic chamber, abnormally developed placenta, etc. In regard to the former point--contraction of stigmatic chamber--I may remark that it does not appear to be absolutely necessary that the pollen-masses penetrate this chamber for effecting fecundation. Thus a raceme was produced upon a plant of A. Loddigesii in the Botanic Gardens here lately; upon this I left only six flowers. These I attempted to fertilise, but with two only of the six have I been successful: I succeeded in forcing a single pollen-mass into the stigmatic chamber of one of the latter, but I failed to do this on the other; however, by inserting a portion of a pedicel with a pollinium attached, I caused the latter to adhere, with a gentle press, to the mouth of the stigmatic chamber. Both of these, as I have already remarked, are nevertheless fertilised; one of them I have cut off for examination, and its condition I will presently describe; the other is still upon the plant, and promises fair to attain maturity. In regard to the other four flowers, I may remark that though similarly fertilised--part having pollinia inserted, others merely attached--they all withered and dropped off without the least swelling of the ovary. Can it be, then, that this is really an [andro-monoecious] species?--part of the flowers male, others truly hermaphrodite. In making longitudinal sections of the fertilised ovary before mentioned, I found the basal portion entirely destitute of ovules, their place being substituted by transparent cellular ramification of the placentae. As I traced the placentae upwards, the ovules appeared, becoming gradually more abundant towards its apex. A transverse section near the apex of the ovary, however, still exhibited a more than ordinary placental development--i.e. [congenitally?] considered--each end giving off two branches, which meet each other in the centre of the ovary, the ovules being irregularly and sparingly disposed upon their surfaces.