LANKESTERIANA


sets. The equally weighted analysis produced 10000+
trees of 1887 steps (CI=0.54, RI=0.85); swapping to
completion on these trees yielded the same set of trees.
A randomly chosen single tree (with bootstrap values
added) is presented in Figs. 4 & 5. The large number
of equally parsimonious trees in the combined analysis
is probably due to the inclusion of the trnL-F data set;
analysis of the matK + ITS data (not shown) produced
only 240 shortest trees.

We also performed a Bayesian analysis of the combined
data set using MrBayes 3.0. The resulting tree (not
shown) has the same topology as the one shown from
the parsimony analysis (Fig. 4 & 5), and Bayesian
posterior probabilities higher than 95% are shown on
the tree together with bootstrap values.

In the combined analysis, Zygopetalinae are highly
supported as monophyletic (see Table 2, Figs.4-5). The
prominently pseudobulbed taxa i ,,. -/, i./..ii, grade)
form a clade in the strict consensus of all shortest trees
but without bootstrap or Bayesian support and most
nodes within this group are weakly supported. Well-
supported clades include Neogardneria + Zygopetalum
+ Pabstia and Galeottia + Zygosepalum + Batemannia.
Cryptarrhena (with two species) is strongly supported
as monophyletic but is isolated on a long branch
basal (without bootstrap support) to Dichaea and the
Huntleya clade. Dichaea, Huntleya, and Chaubardia
are highly supported as monophyletic on long branches;
they are successively basal with strong support to the
remaining taxa of the Huntleya clade comprising the
Chondrorhyncha complex.

In the Chondrorhyncha complex (Fig. 4), only a few
traditionally recognized genera are strongly supported
as monophyletic; these include Chaubardiella,
Chondroscaphe, Dodsonia, Kefersteinia, and
Warczewiczella. Most notably, Chondrorhyncha (as
currently circumscribed) is polyphyletic, with its
members falling into eight highly supported clades,
including Stenia + Dodsonia, Ackermania + Benzingia
+ Chondrorhyncha reichenbachiana, and Bollea +
Pescatorea. However, the combined data set does
not resolve deeper nodes within the Chondrorhyncha
complex.

DISCUSSION

Previous classifications divide Zygopetalinae s.l. into
several groups, recognized either formally as separate
subtribes (Huntleyinae, Zygopetalinae, Warreinae,


Dichaeinae; Szlachetko 1995) or as informal clades
(Dressler 1993). Several grades are recognizable
in our analyses: Huntleya grade (including Dichaea
and Cryptarrhena; pseudobulbs absent or very small,
leaves duplicate); Zygopetalum grade (pseudobulbs
conspicuous, leaves usually convolute); and the Warrea
grade (pseudobulbs of several intemodes, leaves
plicate). Dichaea and Cryptarrhena were often placed
in their own subtribes due to their morphological
divergence from other Zygopetalinae (Dressler 1993,
Szlachetko 1995), but data from rbcL (Cameron et
al. 1999) and matK, trnL-F, and ITS (Whitten et al.
2000, present study) strongly support their inclusion in
Zygopetalinae in spite of their placement on relatively
long branches.

The inclusion of these anomalous genera results
in a subtribe difficult to define with morphological
synapomorphies. Potential morphological characters
defining the subtribe are the (usual) presence of four
superposed flattened pollinia, usually a transverse
slit-like stigma (but Dichaea has a rounded stigma
and variable pollinia), and a column provided
with an infrastigmatic keel (Chondrorhyncha spp.
hereafter treated as the genera Daiotyla, Kefersteinia,
and Warreopsis), a tooth (Kefersteinia) often basal
(Cryptarrhena, Pescatorea, Warczewiczella) or a ligule
(Dichaea). Additional synapomorphies are the violet
color (not purple) present in the flowers of many genera
(Acacallis, Cochleanthes, Dichaea, Koellensteinia,
Otostylis, Pabstia, Warczewiczella, Zygopetalum,
Zygosepalum), a color rarely found in other groups of
Neotropical Orchidaceae, and the obvious tendency of
the group to occupy shady, sub-optimal niches in the
forest canopies (associated with transformations in the
epidermis in Benzingia and many species of Dichaea).

Perhaps the two characters are somewhat correlated,
the lilac color having a special significance in attracting
pollinators in subdued light. Within the Huntleya grade,
perhaps the more useful synapomorphy is the presence
of two apical bracts on the peduncle, a character
widespread among all the genera with the exception
of the many-flowered Cryptarrhena. These bracts
differ greatly between them in shape and size. The
more basal, adaxial bract, which envelops the pedicel
and ovary, as well as the inner bract, is usually large
and cucullate. The apical bract is smaller, ligulate, and
projects beneath the flower abaxial to the lip. Members
of the closely related Lycastinae and Maxillariinae
also possess four pollinia, but the pollinia are usually
globose or slightly flattened, and the stigmas are oval


Vol. 5, N 2