_An epiphyte._ PSEUDOBULBS _oblong, slightly furrowed, from 2 to 4 inches long, clustered together_. LEAVES _2 on each pseudobulb, shining and leathery, oblong-lanceolate, pointed, about a foot long, much shorter than the scape_. SCAPE _upright or nodding, from 2 feet to a yard high, spotted, loosely panicled, bearing from 10 to sometimes probably 50 flowers_. BRACTS _few, short, and membranous, fitting close to the stem_. SEPALS _and_ PETALS _nearly equal, oblong-lanceolate, apiculate, about an inch long, greenish-yellow, barred with dark purplish-brown_. LIP _purple in some varieties, in others white, with a horseshoe-shaped band of purple on its disk, oblong, rather blunt, and slightly lobed at the apex, somewhat heart-shaped at the base, where there is a callosity on either side, and a double carina_. COLUMN _very slightly winged_. This pretty species is well figured in 'Pescatorea,' where it is stated to be a native of Mexico, whence it was introduced by M. Linden, of Brussels. It was from his establishment that I derived the plant that is represented on the other side, and which flowered at Knypersley in May last (1865). It appears to be very easily managed, requiring the same temperature and treatment as _O. læve_, to which it is nearly allied, and which forms the subject of the following Plate. It is also very closely related to _O. Karwinskii_; and I do not feel certain that the two may not eventually have to be united. At present, however, so few plants of either kind exist in the collections of this country, that the materials necessary for an extensive comparison are not forthcoming. The specific name was given by Professor Reichenbach in honour of M. Reichenheim, of Berlin, whose collection of Orchids and other plants has long been celebrated. DISSECTIONS.--1. Side view (_magnified_) of lip and column; 2. Front view of ditto. [Illustration] Plate XVI [Illustration: Odontoglossum læve.] PLATE XVI. ODONTOGLOSSUM LÆVE. SMOOTH-LIPPED ODONTOGLOSSUM. O. (ISANTHIUM) pseudobulbis subcompressis sulcatis diphyllis, foliis oblongo-ensiformibus obtuse acutis apice obliquis, scapis multifloris brevioribus, floribus laxe racemoso-paniculatis, bracteis brevibus membranaceis, sepalis petalisque oblongo-linearibus acutis planis, labelli limbo panduriformi apiculato ungui lævi obsoletissime bidentato, columnæ alis apice rotundatis crispis basi planis. _Lindl._ ODONTOGLOSSUM LÆVE, _Lindl. in Bot. Reg._ (1844), _t._ 39; _L. Fol. Orch._ _n._ 52. Habitat in GUATEMALA, _Skinner_. DESCRIPTION.