is prevailing. Maravaca above the sea, where a humid atmosphere is about thirty miles
N.N.E. direction from Esmeralda.”
The genus Diothonea differs from Isochilus only in having the lip united to the column, by an
intervening membrane, and it therefore bears the same relation to that genus, as is borne to Epiden-
drum by Encyclium. It may therefore be regarded as either a distinct genus, or a mere form of
Isochilus. The original species, however, collected by the late Colonel Hall in the valley of Lloa,
on the western face of the Cordilleras of Peru, has a lip very different in form from the other
divisions of the perianth, and both have a strong double callosity at the base of the fore part of the
lip ; in the true species of Isochilus, on the contrary, the lip has either one tubercle only at that
part, or none at all.
Fig. 1. represents the column and lip of this plant.
Neither this nor the following species have yet appeared in our gardens.
No. 2.
MAXILLARIA EBURNEA.
M. eburnea ; pseudobulbis ovatis suleatis monophyllis, foliis lineari-oblongis acutis
subcoriaceis in petiolum canaHculatum angustatis scapo erecto unifloro
vaginato longioribus, vaginis distantibus acutiusculis, sepalis explanatis late-
ralibus triangularibus elongatis supremo petalisque lanceolatis, labello ovato-
oblongo leviter crenulato callo unico acuto per medium et duobus lateralibus
sejunctis multd minoribus, column^, apice uncata car dine dentato.
This plant is one of the most genuine species of a genus that seems to require reconsideration;
but among whose numerous forms no good marks of division have hitherto been found.
It must be a plant of considerable beauty, for its flowers are nearly five inches from tip to tip of
the lower sepals, and of the purest white. Some of the leaves in my wild specimens are as much as
fifteen inches long, and are remarkable for the long channelled stalk into which they taper at their
junction with the pseudo-bulbs; their texture is more papery than leathery.
The nearest relationship of the plant appears to be with M. grandiflora, which is said to have
compressed 2-leaved pseudo-bulbs, and a lip plaited transversely at the base.
Fig. 2 a represents the column, with its long foot, from which the sepals and petals have been
cut away. 'Fig. 2 b shews the lip with the three callosities upon its surface.