The concept Dienia is now generally referred to the 
genus Microstylis or to the earlier name Malaxis. 
A photograph of the type of Microstyhs gracilis 
shows a plant which is somewhat smaller than that of 
Dienia calycina and with rather laxer inflorescence. How- 
ever, the floral drawing of D.calycina by Lindley agrees 
well with the description of the flower of Microstylis 
gracilis. Moreover, Ames, who has examined the types 
of both species, describes the lip of each as ‘‘transversely 
elliptical.’’ Because of the close vegetative and floral 
similarity between the types, it appears that they should 
be regarded as synonymous. 
Microstylis monticola, of which we have a record of 
the type, is in thorough agreement both vegetatively and 
florally with Dienia calycina. In one example the lower 
flowers of the raceme are very loosely arranged as in the 
type of Microstylis gracilis. 
A drawing of the type of Microstylis microtoides 
shows the single leaf decidedly below the middle of the 
stem, while in the other representatives of Malaais caly- 
cina the leaf is about at the middle of the stem. The only 
other discrepancy from the latter species is that the dorsal 
sepal does not exceed the lateral sepals in size. The ab- 
sence of morphological differences, however, indicates 
that this species is inseparable from Malaais calycina. 
Malaais calycina occurs in Mexico, Guatemala and 
Costa Rica. It is also reported from Peru (Pavon) by 
Ridley. 
Malaxis Ehrenbergii ( Reichb.f. ) O. Kuntze Rev. 
Gen. Pl. 2 (1891) 678. 
Microstyls EKhrenbergu Reichenbach filius in Lin- 
naea 22 (1849) 835. 
Microstyls purpurea S. Watson in Proc. Am. Acad. 
18 (1888) 195. 
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