× Bensteinia ramonensis, a New Natural Hybrid in the Zygopetalinae (Orchidaceae)

2007·0.82 MB·

by  Pupulin, Franco

Selbyana 28(2): 112-116. 2007.
X BENSTEINIA RAMONENSIS, A NEW NATURAL HYBRID IN THE
ZYGOPETALINAE (ORCHIDACEAE)
FRANCO PuPULIN
Jardin Botlinico Lankester, Universidad de Costa Rica. p.o. Box 1031-7050 Cartago,
Costa Rica, CA. Harvard University Herbaria, Cambridge, MA, USA. Marie Selby Botanical
Gardens, Sarasota, FL, USA. Email: [email protected]
ABSTRACT. A new nothospecies in the subtribe Zygopetalinae (Orchidaceae), X Bensteinia ramonensis, is
described and illustrated from Costa Rica, and its relationships are discussed. A summary of natural and
artificial hybridization in the subtribe is offered.
Key words: Orchidaceae, Epidendroideae, Zygopetalinae, natural hybrids, Bensteinia, Costa Rica
The thousands of artificial orchid hybrids pro petalum), and new bi- and tri-generic hybrid
duced for horticultural purposes show that many genera within the subtribe like Propetalum
members of the Orchidaceae are capable of de (=Promenaea X Zygopetalum), Cochlepetalum
veloping viable seeds through intrageneric and [=Cochleanthes (actually Warscewiczella) X
intergeneric crosses, sometimes involving five or Zygopetalum], and Propabstopetalum (=Prope
six different genera. In many advanced orchid talum X Zygopabstia).
groups, artificial hybridization has revealed low Among the usually pseudobulbless, condupli
levels of genetic incompatibility among mem cate-leaved, one-flowered genera of the Huntle
bers of related genera, and it is likely this leaky ya clade (Whitten et al. 2005), 9 intergeneric
barrier allows in the wild some gene exchange hybrids have been recorded (Dressler 1981,
to add to the genetic pool. With a few notable Shaw 2005). Of these, only the hybrids between
exceptions, interfertility usually decreases with Benzingia sp. and Kefersteinia sp., and between
genetic divergence in more distantly related taxa Cochleanthes aromatica (Rchb.f.) R.E.Schult. &
and, as a general rule, is higher within subtribes. Garay and Warscewiczella discolor (Lindl.)
Nevertheless, natural hybridization is relative Rchb.f., occur naturally. The first was found
ly uncommon in the family. In natural popula only once in the Amazonian region of Ecuador,
tions, reproductive isolation is maintained along the Rio Pastaza (Neudecker 1994, Dodson
through several distinct barriers, including pre & Luer 2005), while the latter is an infrequent
pollination mechanisms (mainly geographic, epiphyte recorded from the Caribbean watershed
temporal, and dependent on floral structure and of the Costa Rican mountain chains (Dressler
ethology) and sexual incompatibility. Among 2003). Another natural hybrid had been recorded
isolating mechanisms, pollination seems espe in the Huntleya clade between Pescatorea
cially critical in the Orchidaceae. Hybrid unfit Rchb.f. and Bollea Rchb.f., but recent molecular
ness, i.e., low viability and failures in attracting analyses (Whitten et al. 2005) reveal that the
suitable pollinators, may also account for the two taxa are congeneric.
scarcity of hybrids in nature. Natural hybrids are The occurrence of a natural hybrid between
usually restricted to intrageneric crosses and the genera Benzingia (as Ackermania Dodson)
crosses among closely related genera. and Kefersteinia was first recorded by Neudeck
The subtribe Zygopetalinae encompasses 35 er (1994) on the basis of a plant growing among
Neotropical genera and some 400 species, main mixed popUlations of Benzingia caudata (Ack
ly characterized by the presence of four flat erman) Dressler, Kefersteinia sanguinolenta
tened, superposed pollinia, a narrow stigma, and Rchb.f., and K. vollesii Jenny (=K. pusilla C.
a tissue extension on the ventral surface of the Schweinf.). More recently, Dodson & Luer
column. Dressler (1981) recorded 22 intergener (2005) suggested as the putative parents Acker
ic hybrids in the subtribe, mostly artificially pro mania palorae (Dodson & Hirtz) Dodson & Es
duced with horticulturally relevant species of cobar [=Benzingia palorae (Dodson & Hirtz)
Zygopetalum Hook. A review of novel hybrids Dressler] and Kefersteinia lojae Schltr. Although
in the Zygopetalinae was recently done by Shaw the flower of the natural hybrid is strongly rem
(2005), who recorded both intergeneric hybrids iniscent of Benzingia in gross morphology, the
with members of the allied subtribe Lycastinae red-purple spotting on the petals and the lip, and
(Lycabstia = Lycaste X Pabstia, and the tri-ge the finely undulate margins of the lip midlobe,
neric Takakiara = Lycaste X Pabstia X Zygo- show a genetic influence of Kefersteinia. Neu-
112
PUPULIN: x BENSTEINIA RAMONENSIS 113
decker (1994) intended to publish the new noth Herba epiphytica caule abbreviato foliis condupli
ogenus with the name of Ackersteinia but, prob catis petiolatis anguste elliptico-oblanceolatis acurni
natis ad 15 cm longis, floribus intermediis inter Ke
ably because of a typographical error, the pro
tologue described the new taxon as an intrage fersteiniam excentricam Dressler & Mora-Ret. et Ben
zingiam reichenbachianam (Schltr.) Dressler, sepalis
neric hybrid of Ackermania; moreover, due to
lateralibus patentibus, labello excentrico alba maculis
the lack of reference to the location of the ho purpureis notato, columnae facie abaxialis carina hu
lotype, the publication of the new nothospecies rnilis instructa, pollinarii stipite lanceolato-elliptico ab
was invalid, and the name X Ackersteinia dod breviato viscidioque subquadrato parvo munito (atque
sonii was validated by Dodson & Luer only in K. excentricam), floris amplitudine, labello integra,
2005. The same orchid genus Ackermania was calla humili labelli pars media attingens, columna
published without explicit indication of the type, elongata (atque B. reichenbachianam). Typus: Costa
and it is therefore invalid; furthermore, the ge Rica, D. Bogarfn 1923 (holotypus, CR-Spirit).
neric name Ackermania in the Orchidaceae is Plant epiphytic, caespitose, without pseudo
likely predated by the fungal genus Ackerman bulbs, the abbreviated stem enclosed by 4-5 im
nia Pat. bricating sheaths, the upper ones foliaceous.
Molecular data show a close relationship be Leaf petiolate, conduplicate, narrowly elliptic
tween Ackermania, Benzingia, and Chondro oblanceolate, acuminate, dark green, 8.5-20 X
rhyncha reichenbachiana, which form a highly 0.9-1.5 cm. Inflorescence lateral, from the axil
supported clade and should be treated as a single of the lower sheaths, I-flowered; peduncle te
genus (Whitten et al. 2005). Although these taxa rete, patent to pendent, to 3 cm long, provided
are diverse in flower morphology (probably as a with an ovate, conduplicate bract, 5 mm long,
result of different pollination systems), they are near the base. Floral bract double, conduplicate,
vegetatively very similar, with pendent, glau the external one widely ovate, 4 mm long, the
cous grey-green leaves, provided with papillose internal bractlet ligulate, 5 mm long. Ovary ped
leaf cells in the upper epidermis. Benzingia hav icellate, to 1.5 cm long including the pedicel.
ing priority over the illegitimate name Acker Flower proportionately large, the sepals pale
mania, the two species of the latter genus were crearnish white, flecked reddish-purple, the pet
recently transferred by Dressler to a broadened als creamish white, heavily spotted and blotched
concept of Benzingia (in Whitten et al. 2005). with purple, the lip creamish white, spotted pur
The generic name Benzingia, originally pub ple, the spots forming 5-7 nectar guides toward
lished without explicitly indicating the type the apex of callus; the callus spotted purple.
(Dodson 1989), was revalidated by Dodson and Dorsal sepal narrowly elliptic, acuminate, con
Romero (1995), together with the two species at cave, hooked at apex, 16 X 6 mm. Lateral se
that time assigned to the genus. In consideration pals narrowly elliptic-Ianceolate, subacute,
of the new generic alignments of the taxa in the spreading, concave, conduplicate-folded toward
group, Christenson (2006) renamed the hybrid the base, 20 X 5 mm. Petals elliptic, rounded,
between Ackermania [=Benzingia] and Kefer apiculate, 14 X 8 mm. Lip excentric, slightly
steinia as X Bensteinia, making the new com twisted toward the right side, elliptic-obovate,
bination X Bensteinia dodsonii (Neudecker) obscurely 3-10bed, obtuse, the apical margin
Christenson. crenulate, the basal margins erect toward the
During the systematic collections aimed to column, 18 X 15 mm; disc with a low, bilobed,
ward the preparation of a treatment of the sub irregularly toothed callus, born toward the mid
tribe Zygopetalinae for the Flora Costaricensis dle of the lip lamina, ca. 2 X 8 mm. Column
(Pupulin in prep.), a plant native from the wet straight, clavate, footed, 15 mm long, the ventral
forest of the Cordillera de Tilaran in Costa Rica surface sparsely woolly toward the margins, pro
appeared, with flowers that exhibit intermediate vided with a low, glabrous, substigmatic keel;
characters between Kefersteinia and Benzingia. the stigma transversal, narrow. Anther cap
It is described here as a new natural hybrid: ovate-elliptic, cucullate, 2-celled. Pollinia 4,
subsigmoid, in 2 pairs of different size, on an
X Bensteinia ramonensis Pupulin, nothosp. elliptic-ovate, hyaline stipe, ventrally provided
nov. Type: Costa Rica-Alajuela: San Ra with an indistinct, subquadrate, hyaline visci
mon, Angeles, Reserva Biologica Alberto dium.
M. Brenes, lOo13'08.5"N, 84°35'48.4"W,
HABITAT: Epiphytic in shade in extremely wet
900-1000 m, Saino trail, tropical wet, tran
premontane forest, at about 1000 m elevations,
sition to premontane wet forest, 25 Septem
along the Caribbean watershed of the Tilaran
ber 2005, flowered in cultivation at Jardin
mountain range in northern Costa Rica. Flow
Botanico Lankester, 7 October 2005, D. Bo
ering occurs at least in September-October.
garfn 1923 (holotype, CR-Spirit).
FIGURES 1, 2. DISTRIBUTION: Known only from Costa Rica.
114 SELBYANA Volume 28(2) 2007
F
10 em
FIGURE 1. x Bensteinia ramonensis. A. habit. B. flower. C. dissected pecianth. D. column and lip, lateral
view. E. column, ventral and three quarter views. F. pollinariurn (three views) and anther cap. Drawn by the
author from the holotype.
PUPULIN: x BENSTEINIA RAMONENSIS 115
FIGURE 2. Flower of X Bensteinia ramonensis. Scale bar = 1 cm. Photograph by D. Bogarin of the flower
that served as the holotype.
ETYMOLOGY: Named from the orchid rich re ana the blotches of this color are usually re
gion of San Ramon in Costa Rica, where the stricted to the central portion of the lip, where
natural hybrid was found. they form five to seven distinct nectar guides.
Finally, the pollinarium of Bensteinia present
A single plant of Bensteinia appeared within
two sets of subsigmoid pollinia on a small lan
a mixed collection of Zygopetalinae from the
ceolate stipe, adaxially provided with a subquad
Alberto M. Brenes Biological Reserve, in north
rate, indistinct viscidium; in B. reichenbachiana
ern Costa Rica. The plant habit was reminiscent
the pollinia are straight and the stipe is subequal
of that of Benzingia, with long-petiolate, narrow,
to the pollinia.
dark grey-green and somewhat glaucous leaves.
This last set of characters is consistent with
The upper epidermal leaf cells are papillose in
the shape and color of Kefersteinia excentrica
Benzingia, whereas they are smooth in the other
flowers. This species was originally described
genera of the Huntleya clade. Benzingia rei
from the wet forests of the Talamanca mountain
chenbachiana (formerly Chondrorhyncha) is a
chain in Costa Rica, but Pupulin (2001) and Go
common epiphyte at A.M. Brenes Reserve (Go
mez-Laurito & Ortiz (2004) also recorded it
mez-Laurito & Ortiz 2004; photograph in Pup
from the A.M. Brenes Reserve. In Costa Rica it
ulin 2005a: 104) and all along the Caribbean wa
is an uncommon epiphyte in premontane wet
tershed of the Tilaran and Central Volcanic rang
forests, where it usually establishes on mossy
es in Costa Rica, where it grows on shaded spots
tree trunks in shady sites, at elevations of 1000-
at elevations of 1000-1500 meters.
However, the flower of Bensteinia markedly 1500 meters. The lip of K. excentrica is distinct
differs from that of Benzingia. The lip is excen ly "off-center" when observed from the front
tric with respect to the bilateral symmetry of the (hence the specific epithet), and this character is
flower, slightly twisting toward the right side. probably designed to drive the pollinator along
Moreover, the lateral sepals do not turn back and the margin of the lip, in order to place the pol
are not hooked as in B. reichenbachiana, and linarium on the basal segment of its antenna
the dorsal sepal is subequal to the lateral sepals, (Dressler 1981: 248). Also, the lip of K. excen
whereas in B. reichenbachiana it is distincly trica presents two small apical lobes, and a rem
smaller. In Bensteinia ramonensis the sepals and nant of these lobes can be observed on the distal
petals are flecked, spotted, and blotched with portion of the lip of Bensteinia ramonensis.
purple, contrasting with the uniform pale cream Nevertheless, the morphology of the callus on
color of the flower segments in B. reichenba the lip of B. ramonensis markedly differs from
chiana, and the lip is almost completely covered that of K. excentrica. The latter has been as
by purple blotches, whereas in B. reichenbachi- signed to the Sect. Umbonatae by Senghas and
116 SELBYANA Volume 28(2) 2007
Gerlach (1993) due to characteristic stipitate cal of the genus Benzingia (Zygopetalinae: Orchida
lus, and Szlachetko (2003) elevated it to the ge ceae). Lindleyana 10(2): 74.
neric rank with the name Senghasia. The section Dressler, R.L. 1981. The Orchids: Natural History and
Classification. Harvard University Press, Cam
includes three species in Costa Rica (Pupulin
bridge, Massachusetts, USA.
2001, 2005b), but none of the other two species
Dressler, R.L. 2003. Orchidaceae. Pp. 216-255 in B.E.
has never been recorded from the Preserve. The Hammel, M.H. Grayum, C. Herrera, and N. Za
general morphology of the column of Bensteinia mora, eds. Manual de Plantas de Costa Rica, Vol.
agrees with that of Benzingia, lacking the sub 3. Monocotiled6neas (Orchidaceae-Zingibera
quadrate plate on the ventral surface that is char ceae). Monogr. Syst. Bot. Missouri Bot. Gard. 93.
acteristic of Kefersteinia; nevertheless, it bears a G6mez-Laurito, J. and R. Ortiz. 2004. Lista con ano
taciones de las Angiospermas de la Reserva Biol-
low ventral keel, probably analogous to the
6gica Alberto Brenes (rnicrocuencas de los rios
weak median keel on the plate of K. excentrica.
San Lorenzo y San Lorencito), Costa Rica. Lan
kesteriana 4(2): 113-142.
Neudecker, T. 1994. X Ackersteinia dodsonii, un nuevo
ACKNOWLEDGMENTS
hfbrido intergenerico en la Subtribu Huntleyinae.
Orquideologia 19(2): 25-28.
I am deeply indebted to my colleague Diego Pupulin, F. 2001. Contributions to a reassessment of
Bogarin, of Lankester Botanical Garden, for col Costa Rican Zygopetalinae. The genus Keferstei
lecting and photographing the plant used for this nia Rchb.f. Ann. Naturhist. Mus. Wien. 103B:
study, and for the useful discussions on its ge 525-555.
neric placement. Wild specimens intended for Pupulin, F. 2005a. Chondrorhyncha Lindl. Pp. 100-
109 in F. Pupulin et al., eds. Vanishing Beauty
this study were obtained through scientific col
Native Costa Rican Orchids, Vol. 1: Acianthera
lection permits No. 36702 and 36891 issued by
Kegeliella. Editorial de la Universidad de Costa
the Costa Rican Ministry of Environment and Rica, San Jose.
Energy (MINAE) and National System of Con Pupulin, F. 2005b. Kefersteinia Rchb.f. Pp. 390-399
servation Areas (SINAC), whose cooperation I in F. Pupulin et aI., eds. Vanishing Beauty-Na
sincerely acknowledge. Part of this study has tive Costa Rican Orchids, Vol. 1: Acianthera-Ke
been sponsored by the Darwin Initiative, UK, in geliella. Editorial de la Universidad de Costa
the framework of the project "Conservation and Rica, San Jose.
Senghas, K. and G. Gerlach. 1993. Tribuss: Maxillar
Monitoring of Meso-American Orchids."
ieae. 59. Subtribus: Huntleyinae. pp. 1617-1674
in Schlechter, ed. Die Orchideen, 3. Aufl., Bd. 1.
Paul Parey, Berlin.
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