My dear Sir

I am much obliged to you for your kind letter (without date)¹ in which you ask about the number of capsules produced by the Maxillaria with the larger pods.² I am told by a french collector M. Gautier that it is the Maxillaria tetragona; however his names are not always to be relied upon.—³ On large plants growing on rocks and covering often more than a square-foot you may sometimes find half a dozen or more, whilst smaller plants growing on trees yield rarely more than one or two. I think that hardly 20% of the flowers produce seed-capsules.⁴ The species is interesting in some other respects also. The bifid pedicelli of the pollinia execute the same movement, you have described in Maxillaria ornithorhyncha, the right and left pollen masses are connected by an elastic tissue like that of the caudicle.⁵

Whereas in all other Vandeae, I examined (Notylia, Cirrhaea, Ornithocephalus, Polystachya, Aëranthus, Oncidium, Cyrtopodium and several other species of Maxillaria), the margins of the valves of the seed-capsules are beset with hygroscopic hairs, I could not find them in the ripe pods of this species; but there are some scattered and rudimentary hairs in the young capsules.⁶

I send you pollen-tubes taken out of a young pod of this Maxillaria showing the fringes which from the six longitudinal ribbons extend between the ovula. On comparing these pollen-tubes with those of Cattleya Leopoldi⁷ you will be struck by a remarkable difference.

In Maxillaria (and with a single exception in all our Vandeae) the pollen-tubes remain fresh in their whole length; in Cattleya (as well as in all our Epidendreae) the upper part of the pollen-tubes soon becomes dry and black; this evidently is a consequence of the stigmatic chamber being shut in Vandeae, whilst it remains open and the pollen exposed to air in Epidendreae.⁸

I already told you in my last letter, that in Notylia and in Oncidium flexuosum, pollen and stigma of the same plant act, as it were, as a poison on each other; this is also the case with the curious Oncidium unicorne and with another species which seems to be nearly related to Oncidium pubes.⁹

I have had numerous racemes of a second species of Cirrhaea (perhaps the C. dependens Rchb. f.) interesting by the extreme variability of the colours of its flowers. I could not fertilize this species with fresh pollinia whilst it might be done easily after they had dried half an hour or an hour.¹⁰ This probably will prevent the flowers being fertilized with the same plants pollen. The disk in this species is provided with a hook facilitating its being taken away.

There begins now to flower here a curious small Orchid, viz. Ornithocephalus.

The anther-bed has a small transverse ridge on the anterior margin; the pedicellus of the pollinium passing over this ridge forms an obtuse angle; as soon as the pollinium is removed by an elastic binding of the pedicellus, this obtuse angle is transformed into a very acute one and subsequently by an hygroscopic movement, the pedicellus is curved in a very singular and elegant manner. In water the pedicellus returns to the former form.¹¹ The two pods of Monachanthus which I fertilized (Dec. 25) with pollen of Catasetum mentosum are now already 7 cm long and as much in circumference.¹²

The plant of Oncidium flex., on which I had fertilized some flowers simultaneously with pollen from a distinct plant of the species and with pollen of Epidendrum Zebra, having perished by an accident I have repeated the experiment on another plant; the result has been the same and I have satisfied myself that it is indeed the side of the Epidendrum-pollen which grows less and that of the Oncidium-pollen which grows more rapidly.¹³

I have made in the first weeks of January a pleasant excursion on the continent, up the river Cubatão to the German colony Theresopolis;¹⁴ and have brought home a fine collection of living Orchids, among which a large plant probably belonging to the Catasetidae¹⁵   You state in your Orchis-book that there are flourishing in your neighbourhood 13 species of Orchids; now on the Cubatão you may collect on the branches of a single old Cedrela-tree even a larger number of species: half a dozen Maxillariae, four or five small Pleurothallidae, a couple of Oncidia, the Leptotes bicolor etc. The beautiful Miltonia cereola was very abundant.—¹⁶ The most striking feature of the Orchid-flora of Theresopolis was the abundance and variety of Maxillariae and the entire absence (as far I have seen) of the Cattleyae, the Amphiglott Epidendra,¹⁷ the Brassavola, which are the dominant littoral forms. Epidendra in general seem to be much more rare than here, where I already know 13 species....