At the time (1864) when this Monograph was commenced, the successful application of the system of cool treatment to Orchids accustomed to a moderate temperature in their native haunts gave a fresh impulse to the cultivation of that charming tribe of plants. By its means, what might almost be regarded as a new Orchid-world, teeming with interest and beauty, was suddenly brought within our reach. A fresh field was opened to the enterprise of collectors, the spirits of cultivators revived, and the hopes of botanists mounted high. Foremost among the spoils that we sought to secure, stood the various members of the genus Odontoglossum, which from the days of Humboldt^[1] and Lexarza, was known to abound in species pre-eminent for the loveliness and delicacy of their flowers but which had hitherto mocked the utmost efforts of our most skilful growers. For although (thanks to the labours of Warczewitz and Lobb) the Horticultural Society and Messrs. Veitch had more than once received large consignments of Orchids—among which were many Odontoglossa—from the mountain ranges of New Grenada and Peru, they had invariably succumbed under the stifling atmosphere to which, in common with the denizens of India, Guiana, or Madagascar, they were remorselessly consigned. Here and there, indeed, an accidental success was achieved in a greenhouse, but the hint was turned to no account, and as a rule—notwithstanding the repeated warnings and remonstrances of Mr. Skinner, Warczewitz, and others—for thirty years we persisted in the incredible folly of growing "cool" Orchids in "hot" stoves; so deeply rooted in the minds of horticulturists was the original prejudice! But it yielded at last, and no sooner had a few houses—constructed and managed on the cool-culture system—made it clear that the Orchids of temperate regions were prepared to submit to the skill of the cultivator, than a general raid was made upon the more accessible countries in which they were known to abound—more especially certain districts in Mexico and New Grenada. To the latter country, collectors were simultaneously sent off by the Horticultural Society, who despatched Mr. Weir; by Mr. Linden, of Brussels; and by Messrs. Low, of the Clapton Nursery; and all these rival envoys, much to their own mortification and chagrin, found themselves sailing for the same destination in the same steamer on the same errand!

It was now that the idea occurred to me of devoting a work of adequate dimensions to the illustration of the particular genus, which from the dried specimens in our herbaria, the plates in Pescatorea, the figures of Humboldt, and the descriptions of travellers was evidently destined to hold the first place among all the numerous company of cool Orchids; and thus began the present Monograph. I had expected that after the work of importation had fairly commenced, not only would the species described by Lindley and Reichenbach be easily obtained, but that along with these a multitude of others entirely new to science would likewise be received. In this respect, however, the results have scarcely come up to expectations; a circumstance that is partly to be accounted for by the difficulty attendant on their importation,^[2] but which is owing, I grieve to say, in a far greater degree to the untimely deaths of those zealous collectors, Bowman and Pearse, who, when in the very heart of the cool Orchid regions of Ecuador and Peru, succumbed under the pressure of their arduous labours. In Mexico, from which much novelty was expected, little has been added to the number of Odontoglossa previously known, and the same may be said of Costa Rica, notwithstanding the vigorous exertions of Mr. Endries. But in these countries it is evident that the genus is not so fully developed as in the mountain ranges of New Grenada, Quito, and Peru. From the latter country little indeed has yet been received, although the eastern slopes of its Andean chain are probably richer in species of unknown or unimported Orchids than any other portion of the globe. But we must await further improvements in the navigation of the affluents of the mighty Amazon, before we can hope to receive any large instalment of these much-coveted treasures.

A combination of the various causes referred to above, by limiting the choice of materials, has seriously delayed the publication of this work, which I had hoped would by this time have reckoned at least a dozen parts. But as there seems to be no immediate prospect of these hindrances to more rapid progress being taken out of the way, and as the sands of my life are fast running out, I have thought it best in the interests of my subscribers, to make the present number the last. The six parts now published will, however, form a volume of convenient size, and one which may, as I trust, serve to show how rich New Grenada is in the members of this glorious genus. What wealth of Odontoglossa Peru may possess, I must leave some future botanist to unfold. He will have a pleasant task, and will probably have doubled the roll of the genus as now known, before his work is done.

During the progress of this Monograph a curious incident has occurred, which may deserve a brief notice. When the publication was commenced, the introduction of two particular plants—more perhaps than of any others known to orchidists—was earnestly desired by growers, these two being the Odontoglossum crispum of Lindley, and the Cuitlauzina pendula of Lexarza. The finding, or rather the re-finding of the former—so magnificent were the specimens in the Lindleyan Herbarium—was declared to be worth a king's ransom; while for the latter—described as a native of Oaxaca—more than one collector had scoured that province in vain. Strange to say, they were already in our grasp: the 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.