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.