Euthonaea imbricata Reichenbach filius in Bot. Zeit. 
10 (1852) 772. 
Euthonaea oppositifolia Reichenbach filius in Bot. 
Zeit. 10 (1852) 772. 
Hewxisea imbricata Reichenbach filius in Walp. Ann. 
6 (1862) 470. 
Hewisea oppositifolia Reichenbach filiusin Walp. Ann. 
6 (1862) 470. 
A careful examination of Heaisea bidentata, supple- 
mented by a drawing of this concept from the Lindley 
Herbarium, together with numerous collections reason- 
ably referred to this concept, has convinced me that it 
should be regarded as distinctly separable from the con- 
cept described as Diothonea imbricata Lindl. and Epi- 
dendrum oppositifolium A. Rich. & Gal. The point of 
separation of these closely similar forms lies in the lip. 
In Heaisea bidentata the lip is adorned at the base with 
a more or less distinct thickening, whereas in Heaisea 
imbricata the lip has a well-marked bicarinate callus at 
the base. In numerous specimens referred to the latter 
concept, the lip is prevailingly flat with more or less in- 
volute sides, as shown by the drawing of the type of 
Diothonea imbricata (l.c.). 
This variety is recorded from Mexico, throughout 
Central America to Panama and from Colombia and 
Peru. 
Diothonea exasperata C. Schweinfurth sp. nov. 
Herba epiphytica, tenuis. Caulis gracilis, laxus, sim- 
plex vel paulo ramosus, vaginis tubulatis arctis omnino 
celatus. Folia disticha, linearia vel lineari-lanceolata, 
apice abrupte rotundata et apiculata, basi sessilia. Race- 
mus terminalis, pendulus, brevis, subdense multiflorus. 
Flores minores. Sepala appendicibus conspicuis dorso 
praedita. Sepalum dorsale elliptico-lanceolatum. Sepala 
[ 107 ] 
