O. crispum being none other than my O. Alexandræ, while—as explained under Plate VIII.—the Cuitlauzina proves to be identical with the long previously introduced Odontoglossum citrosmum of Lindley. Whether all the botanical pressure that can be brought to bear upon our cultivators may suffice to convert O. Alexandræ into O. crispum, or change O. citrosmum into O. pendulum, is an extremely doubtful question, so strong is the hold that the erroneous names have already secured on the public mind. In the parallel case of Wellingtonia, that popular Conifer—though now almost universally admitted to be a Sequoia—remains Wellingtonia still, and seems likely to do so for all time to come.

The range of the genus Odontoglossum, as may be gathered from the descriptions attached to the various Plates, is of a peculiar character, being at once restricted and extensive. It is restricted, for it never leaves the Andes, and it is extensive, for it is found in all parts of that vast mountain-chain, from the confines of Florida to the frontiers of Chili. As yet no species has ever been met with at a lower elevation than 2500 feet above the sea-level, nor, with the exception of O. hastilabium, has any Odontoglossum been known to descend so low;—the most usual altitude being 5-6000 feet, though a higher point is often reached. Like the humming-birds which frequent the same mountains, and vie with them in beauty, nearly all the Odontoglossa are exceedingly local, and in this way two of the most beautiful species, e.g., O. vexillarium and O. Roezlii, eluded discovery for many years, even in a region supposed to be well explored by collectors.

As to the botanical limits of the genus, I must needs confess that they are exceedingly difficult to fix. It is as true now as when Professor Lindley first made the observation to me, that "The more we build up the partition walls between Odontoglossum, Oncidium, &c., the more the species break them down." Certainly no one at first sight would suppose Odontoglossum cariniferum was anything but an Oncidium, nor Oncidium macranthum other than an Odontoglossum. Indeed, I must own to a suspicion that ultimately both these genera, together with Miltonia, Mesospinidium, Aspasia, and possibly one or two others, may come to be regarded merely as sub-genera, But this difficult question is safest left in Professor Reichenbach's far abler hands. At the same time, it is not to be denied that there is such a peculiar look about the Odontoglossa, that even a non-scientific observer has seldom any difficulty in at once referring most of the species to their true position.

One other matter remains to which I must very briefly advert. Mr. Darwin's fascinating work on the "Fertilization" of Orchids has led many persons to suppose that this beautiful tribe lends an exceptional amount of support to the theory with which that ingenious writer's name is so prominently associated, but there could scarcely be a greater mistake. Not only is the theory in question utterly rejected by Professor Reichenbach, the facile princeps of living orchidists, but the greater our knowledge of the order, the less countenance does it seem to yield to the Darwinian view. We have now become perfectly well acquainted with all the genera—we might almost say with all the species—that belong to particular countries, but it is in these that the limits of variation between the different forms are most distinctly defined; in these, too, the great principle of unity in diversity is most conspicuous—the genera holding aloof from each other, and even the species keeping themselves distinct, although the Orchid mark is unmistakeably stamped upon all alike. Mr. Gould has remarked, in his great work on the "Trochilidæ," that the Darwinian theory derives no support from them, and the same may be safely affirmed of Orchids, which—we are now speaking of America—are the humming-birds' constant associates. Neither, while we contemplate the marvellous and inexhaustible variety of form by which the order is distinguished above all its fellows, can any plead that this result is due to its ancient lineage, nor yet to the vast periods through which endless transformations are assumed to have been continually taking place, because Orchids—according to geologic reckoning—are but a thing of yesterday, and have never been found in a fossil state. Yet their constant companions the Ferns, trace back their pedigree to the earliest vegetation of the primeval world! To the believer, however, the problem is not hard to solve. Ferns and other flowerless plants came early in the Divine programme, because the coal, into which they were to be ultimately converted, had need to be long accumulating for the future comfort and civilization of our race; while the genesis of Orchids was postponed until the time drew near when Man, who was to be soothed by the gentle influence of their beauty, or charmed by the marvellous variety of their structure, was about to appear upon the scene. There are multitudes who could bear witness how amply, in their own experience, this gracious purpose has been fulfilled; while the writer—in whose breast a love of Orchids prevailed from his youth up—can only exclaim with the Psalmist, "Thou, Oh Lord, hast made me glad through Thy works, and I will rejoice in giving thanks for the operation of Thy hand."

J. B. 

 Knypersley Hall, April 24th, 1874.

LIST OF PLATES.