218 MR. R. A. ROLFE ON THE APOSTASIER. 
or quite glabrous in Apostasia (fig. 15) and Neuwiedia Zollingeri, 
but more or less puberulous in other species of the latter genus. 
Perianth-segments.— The perianth-segments in both genera are 
lanceolate or lanceolate-linear, and more or less distinctly cuspi- 
date (see numerous figures); in Apostasia (fig. 15), also in Neu- 
wiedia Zollingeri,nearly or quite glabrous ; but in other species 
of Newwiedia (see figs. 2 and 3) the three outer segments, or sepals, 
as well as the central keel of the three inner ones (the only part 
exterior in the bud), are puberulous or shortly pubescent. In 
Apostasia the six segments are subsimilar and subequal, no real 
difference in the petals and no differentiation of the median one 
into a lip being perceptible. All the segments are strongly, but 
obtusely, keeled, and shortly cuspidate. In Neuwiedia, however, 
the petals are a little broader than the sepals, very slightly oblique, 
while the lip, in other respects similar to the petals, is a little 
broader, quite equal-sided, and with a slightly thickened, linear, 
fleshy keel inside, in addition to the outer one, both of course 
being simply thickenings of the central nerve (see figs. 4 to 6, also 
10). The sepals are also keeled, perhaps not quite so strongly 
as are those of the inner segments, especially in N. Grigithi 
(fig. 4); and all the segments are shortly euspidate. The 
margins of the petals and lip, which are interior in the bud, are 
glabrous. 
Column.—The column, which is altogether homologous with 
that of other Orchids, is extremely short in Apostasia (figs. 18, 21, 
23, and 28), and in Newwiedia Griffithii (fig. 7), but half a line 
long and sometimes over in other species of the genus (see fig. _ 
11). It is flattened from front to back, the angles being some- 
what acute. 
Stamens.— Three perfect stamens are present in Neuwiedia 
(figs. 7, 10, 11, and 13), but only two in Apostasia (figs. 17, 21, 
23, and 28); the third one, homologous with the staminode of 
Cypripedium, is present in the section Mesodactylus as a barren 
filament-like organ, always more or less adnate to the back of the 
style (figs. 23 and 28), while in the section Adactylus it is entirely 
absent (figs. 17, 18, and 21). Two of these stamens are opposite 
the petals, being the lateral stamens of the inner stamina! whorl 
(see fig. 1), while the third one is opposite the dorsal sepal, and 
is the median or dorsal stamen of the exterior staminal whorl 
(see fig. 1). The lateral stamens of the outer whorl and the 
median one of the inner whorl are entirely wanting, while in the 
