Should Phalaenopsis hieroglyphica and Phalaenopsis lueddemaniana be merged as one species?
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| Phalaenopsis hieroglyphica or P. lueddemaniana? |
If
you are a long time orchidist who is well-informed with how present species
were treated during their early history, you might think that the question
above is a long outdated one, and one that has already been resolved almost 40 years
ago, when Dr. Herman Sweet’s The Genus
Phalaenopsis was published. In it, he mentioned, for Phalaenopsis hieroglyphica, “Although this species was recognized
as a variety of Phalaenopsis
Lueddemaniana, I fail to find any connecting links in the variation pattern
of P. Lueddemaniana, both in color
and morphology, which would include such extremes as this species exhibits. The
unique color pattern, the very distinct basal callosity coupled with the
unusually large size of the flower indeed warrant the recognition of a specific
status”.
However,
after seeing a good number of specimens from the two taxa from many parts of
the country where they occur, I kept on encountering plants whose flowers appear to fall midway between the supposed distinguishing characters of both P. hieroglyphica and P. lueddemaniana. But first, let’s
review the two taxa.
Botanical history and description
1.
Phalaenopsis lueddemaniana
Phalaenopsis lueddemaniana, the older of the two, was described
by the younger Reichenbach in 1865 and was based from a plant cultivated, by M.
Lueddeman, in Paris. Lueddeman was said to be the first European to have the
flowered the species, although other plants also flowered simultaneously in
several collections at about the same time. At the period of its introduction,
by Hugh Low, some of the plants were thought to be P. equestris and were thrown away until the remaining plants
flowered and the mistake realized. The type locality is not known.
The currently
known range of this species includes the following: Luzon (Apayao, Bataan,
Bulacan, Camarines Norte, Isabela, Kalinga, Laguna, Nueva Vizcaya, Pangasinan,
Quezon, Rizal and Sorsogon); Polillo; Palawan; Leyte; and Mindanao (Agusan, Bukidnon, Davao and Lanao).
Color-wise,
this species possesses some of the brightest hues within section Zebrinae. The ground color is whitish
and ornamented with narrow, transverse bars that break into irregularly shaped
dashes or spots that often coalesce and resemble somewhat illegible
inscriptions toward the apical portions of the sepals and the petals. The bars
are often purple-pink on the basal interiors of the segments, and darken to
(reddish-) magenta along the sides and into the apices. The labellum is
purple-pink with or without whitish margins, while the sidelobes are a paler
color but are a conspicuous yellow at their front. Two named varieties (more
correctly demoted to forma status),
var. delicata and var. ochracea, both have ground colors
ranging from pale yellowish to white with transverse bars that are ochre to
cinnamon-colored, and their respective labella are said to be amethyst-purple,
although it is far paler in the latter. The main distinguishing character that
separates the two is that in var. delicata,
the basal halves of the segments are barred with amethyst-purple, while in var.
ochracea the same basal halves are only
lightly suffused with amethyst-purple and the transverse bars greenish-ochre
instead of amethyst-purple.
Size-wise,
the flowers of P. lueddemaniana are
commonly up to 6 cm across, although it can be smaller in some clones. At the
other end of the range, some flowers can slightly exceed 7 cm in diameter.
In labellum
morphology, the type exhibited a mid-lobe that constricts noticeably toward the
apex and whose margins are devoid of teeth. The adaxial surface is furnished
with a ridge that terminates into a cushion of rather stiff hairs. At the
junction of the lateral lobes and the mid-lobe is a fleshy structure adorned
with short, antrorse papillae, and in front of this structure is a bifid
projection that flanks the ridge mentioned above. The side lobes are obliquely
truncate with irregular apical margins.
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| A brightly colored and almost typical P. lueddemaniana, except for the forked side lobes. |
2.
Phalaenopsis hieroglyphica
Described in
1887, also by the younger Reichenbach, this taxon was originally given a
varietal rank, under P. lueddemaniana, until Dr. Sweet
elevated it to species rank in 1969. The type was based from a collection of
William Boxall that was passed onto Hugh Low. The exact locality where the type
was collected was not specified.
This taxon
has been recorded from Luzon (Apayao and Cagayan); Polillo; Palawan; Leyte; and
Mindanao (Surigao).
In color,
the ground may be white to cream, with some specimens displaying green on their
tips. The coloration of the markings is of varying shades of ochre that become
golden yellow towards the apices of the segments, or suffused with purple
toward the basal fifth. Individually, these markings are more or less
elongated, irregularly shaped dashes and rings that with little imagination can
be interpreted as hieroglyphic-like, hence the name.
In size,
these flowers are usually around 7 cm in diameter, with relatively narrow
segments when compared with P.
lueddemaniana, which is known to have fuller-shaped flowers.
The mid-lobe
of the labellum of the type of P.
hieroglyphica is said to be ‘cuneate-flabellate’ that are ‘obscurely erose
toward apex’ (Sweet, 1980). The erose nature of the epichile margins of P. hieroglyphica is often used as one of
the means of determining flowers of this taxon from P. lueddemaniana, apart from the coloration and markings of the
segments. Other details stated for the labellum of H. hieroglyphica include the following: ‘...from the base to middle
with fleshy keel merging into an ovoid callus covered with prominent hairs, the
claw and the disc between lateral lobes provided with a semi-cylindric, fleshy,
glabrous callus terminating in numerous elongate, acicular digits, in front of
which at junction of mid-lobe and lateral lobes a pair of bifid appendages’
(Sweet, 1980). The lateral lobes are bifid at the apices.
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| P. hieroglpyphica with the margins of the labellum epichile extended outwards like fins and very much unlike the cuneate-flabellate shape seen on the type specimen. This photo illustrates one of the tremendous variations seen on this taxa |
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| A pale-colored P. hieroglyphica |
Discussion
Based from
the information given above for the two taxa, it would seem that the differences
are clear-cut and hence confusion between the two can be readily avoided.
However, a review of various specimens found in various parts of the country
yielded observations that do not fall into our current interpretations on these
two. For example, the width of the labellum in P. lueddemaniana is seldom as narrow as the type seems, and the
margins are often toothed, with the protrusions ranging from barely apparent to
very distinct. As was stated above, P.
lueddemaniana has a single bifid projection situated at the base of the
mid-lobe, while there are two for P.
hieroglyphica, with the smaller pair positioned behind the frontal pair.
However, there are specimens of the former that display two pairs. A look at
the side lobes don’t give any stability either, as there are specimens of P. lueddemaniana that show forked side
lobe apices similar to P. hieroglyphica.
In terms of
markings, there are specimens of P.
lueddemaniana that exhibit very narrow bars that are arranged in such a way
that they evoke those seen in P.
hieroglyphica, although these are mostly confined to the apical halves of
the sepals and the petals. In the case of plants referable to P. hieroglyphica, the markings are much
more consistent in nature, but it is in their coloration that aberrations are
detected. Apart from the usual ochre to (golden-) yellow, there exist specimens
whose markings are in the range of magenta’s spectrum. Even the width of the
segments if fluid: some flowers of P.
lueddemaniana have narrow segments and there are P. hieroglyphica blooms that are wider than what is usual. Indeed,
when presented with intermediate plants of both taxa, any observer will
certainly have a difficult time assessing which should be delegated to P. lueddemaniana, and which to P. hieroglyphica.
As for the
flowering habit, Christenson (2001) noted that “P. hieroglyphica has the habit of simultaneously opening all the
flowers on a plant”. However, I have seen the same behavior on some plants of P. lueddemaniana too, most notably on
large and old plants. Photo below shows one such example:
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| P. lueddemaniana with a cuneate (wedge-shaped) labellum and terminated by a triangular epichile. Note the erose margins. |
Looking closely at the hypochile, we see two bifid projections, encircled in blue. Remember that only one bifid projection is stated to occur on P. lueddemaniana. Could this plant be a P. hieroglyphica instead? Maybe, but the breadth of the perianth segments are more consistent with P. lueddemaniana's, and the markings are a blend of the two taxa in question. This example shows a specimen with the mixed traits of both P. lueddemaniana and P. hieroglyphica.
Another specimen of P. hieroglyphica with a labellum that does not flare at the apex, but still toothed on the margins:
Let us look at a few more examples of both P. hieroglyphica and P. lueddemaniana:
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| The photo above shows a 'P. hieroglyphica' with rather broad petals and sepals, a character that is originally stated for P. lueddemaniana, but not for P. hieroglyphica. |
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| Above is another plant of P. hieroglyphica with flowers having broad petals and sepals |
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| In contrast, this P. lueddemaniana above has the narrow petals and sepals of P. hieroglyphica |
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| A P. lueddemaniana from the province of Laguna with almost hieroglyphic-like markings |
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| The labellum of this specimen of P. lueddemaniana from Quezon is very broad, with minutely erose edges |
Possible solutions
Could it be
that the concept of P. hieroglyphica
proves to be nothing more than a differently marked P. lueddemaniana? The existences of intermediates, those which
connect two extremes, render the delineation of any two presumed closely
related species highly subjective. If the common characteristics weren’t as
numerous, and there exist traits not subject to overlap, then it would have
been easier to amend the description of the two. However, the areas where both
taxa have been traditionally separated- namely flower size, flower color,
flower markings, shape of the side lobe apices, shape and nature of the
midlobe, and the number of bifid projections on the hypochile- have all been
observed to display variations that are easily seen to occur in plants of both P. lueddemaniana and P. hieroglyphica. In this scenario, we can place P. hieroglyphica under the synonymy of P. lueddemaniana, as the latter has priority due to an earlier publication date (1865 vs 1887).
Another possible
solution is to revert to the original diagnosis, where P. hieroglyphica is treated as a variety of P. lueddemaniana, but the problem with this approach is that all the
intermediate forms- and there are many- should also, by default, receive varietal rankings. Given
the number by which these intermediates exist and the range of variations they
show, such an action will invariably produce too many unnecessary names that
have no solid taxonomic standings and whose applications are highly biased and
vague.
Perhaps one
avenue that can be explored is the possibility that P. hieroglyphica is a true species after all, and the anomalous
specimens as swarms of natural hybrids with P.
lueddemaniana. Given that horticultural crosses involving these two taxa
produce progenies whose flowers are very much alike these deviant plants’, such
a theory may be given weight. Furthermore, the presence of only one of the two
putative parents within the presumed natural hybrids is enough to give credence
to the premise of possible introgression. If we take a look at the known ranges
of these two taxa, it is clear that they overlap in Apayao on Luzon, and the
islands of Polillo, Palawan and Leyte. This might suggest that the intermediate
forms may have actually been progenies of scattered hybridization events. An
important note here is that aberrant plants of P. lueddemaniana have been detected on Laguna and Quezon- two
provinces where P. hieroglyphica has
not yet been found. The existence of P.
hieroglyphica on the island of Polillo, east of Quezon, might imply that
this taxon was once or could still be found somewhere on Quezon, and that
deviant plants of P. lueddemaniana
could be borne out of introgression, as was first mentioned by Christenson
(2001). More sampling from other parts of the country is needed to elucidate
this hypothesis, but perhaps it is worth noting that P. hieroglyphica exists on Surigao, where P. lueddemaniana is not known, and where no intermediates have so
far been reported or noted. Understandably, an endeavor such as this will require much patience and resources, but understanding the very nature of plants is what botany is all about. It does not end with merely describing new species, which almost anybody can do given some training.
In 1980, Dr.
Sweet wrote “Unfortunately, the International Registration Authority for Orchid
Hybrids of the Royal Horticultural Society, London, England, no longer
recognizes for registration purposes Phalaenopsis
hieroglyphica as a species distinct from P. Lueddemaniana. This simplistic approach raises havoc with the
scientific nomenclature as well as producing a situation in which highly
heterogenous and different hybrids must be called by names which do not reflect
their true parentage and genealogy”.
However, in
the light of the findings presented in this paper, and if future studies fall
short in proving that hybridization events have perhaps produced the
intermediate plants, then we may need to treat P. hieroglyphica as conspecific with P. lueddemaniana after all, although the repercussions, especially
with the horticultural sector, remains true now as it did when it was first
realized in 1980.
References:
Christenson
E.A. 2001. Phalaenopsis- A Monograph.
Timber Press, Portland, Oregon
Cootes J.E.
2011. Philippine Native Orchid Species.
Katha Publishing Co., Inc.
Sweet, H.R. The Genus Phalaenopsis. Orchid Digest
1980.
Valmayor
H.L. 1984. Orchidiana Philippiniana.
Eugenio Lopez Foundation, Inc., Manila, Philippines.
Glossary
acicular having a very narrow and stiff point
adaxial surface
the frontal or upper
surface
antrorse abruptly bent forwards
bifid split at the apex into two parts
cuneate wedge-shaped
epichile the apex of the labellum
erose irregularly toothed, as if gnawed
flabellate (or flabelliform) fan-like
glabrous smooth
hypochile the basal portion of the labellum
papillae (pl.) papilla (sing.) small, nipple-like protuberances on a given surface
Note: This paper was originally published in the Flora Filipina Primer in 2012, and reprinted on Phalaenopsis (USA) the following year. It is here reproduced with minor changes from the original, in an attempt to make it more widely accessible to interested readers.
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