A new species of Elleanthus (Orchidaceae) from Central America

2018·6.8 MB·English

by  Morales, Fredy Archila

A new species of Elleanthus (Orchidaceae)
from Central America
Fredy Archila Morales1,2 & Guy R. Chiron3
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1Estación Experimental de orquídeas de la familia Archila
2Herbario BIGU, Universidad de San Carlos de Guatemala
3Herbiers, Université de Lyon 1, F-69622 Villeurbanne Cedex (France)
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Abstract
During botanical tours in Alta Verapaz (Guatemala), a plant of the genus
Elleanthus drew the attention of the senior author by the color of its leaves,
intense purple on their abaxial side. After having thoroughly examined it
we came to the conclusion that it was something different from any known
species. It is described here as a new species and compared to its closest
relative, Elleanthus hymenophorus, by means of morphological descriptions,
botanical drawings and photos.
Résumé
Au cours de sorties botaniques réalisées en Alta Verapaz (Guatemala), une
plante du genre Elleanthus a attiré l'attention du premier auteur par la
couleur de ses feuilles, d'un violet intense en partie abaxiale. Une étude
approfondie a montré qu'il s'agissait d'un taxon ne correspondant à aucune
espèce connue. Elle est décrite ici comme espèce nouvelle, comparée à
l'espèce la plus proche, Elleanthus hymenophorus. Sa description est
accompagnée de dessins botaniques et de photographies. C'est une espèce
qui est menacée par la destruction des habitats et une collecte d'autant plus
excessive qu'elle possède des caractéristiques faisant d'elle une plante
ornementale.
Manuscrit reçu le 20/10/2018 Article mis en ligne le 25/10/2018 – pp. 166-171
Resumen
En recorridos realizados en Alta Verapaz, llamo la atención una planta del
género Elleanthus, por el color de sus hojas un morado intenso en la parte
abaxial, al estudiarla detenidamente se pudo establecer que se trataba de
una especie que no encajaba con ninguna de las especies ya descritas, por
lo que después de elaborar los iconos botánicos, el descriptor, su diagnosis,
se presenta como nueva especie y se compara con su pariente más próxima,
Elleanthus hymenophorus. Posee características potenciales para convertirse
en cultivo ornamental.
Keywords: Elleanthus, Guatemala, Neotropics, taxonomy.
Mots clés : Elleanthus, Guatemala, néotropiques, taxinomie.
Palabras clave: Elleanthus, Guatemala, Neotrópico, taxonomia.
Introduction
For most authors the genus Elleanthus C. Presl (1827: 97) belongs to the
subtribe Sobraliinae which has been placed in various tribes among which
the tribe Sobralieae, described by Pfitzer in 1887, and usually considered as
a natural group, at least in parte (Neubig et al., 2011). We must note that
Szlachetko (1991) placed the genus in its own subtribe, Elleanthinae. The
main centre of diversification of Elleanthus is the Andine region; however
the genus is present up to the Neotropical Mesoamerican zone. It is
comprised of ca. 100 species, distributed in tropical America and the
eastern West Indies. In Guatemala Ames & Correll (1952-1953) reported
three species, however two are now placed within Adeneleuterophora
Barbosa Rodrigues (1882: 171): A. linifolia (C. Presl, 1827: 97) Dudek &
Szlachetko (2010: 5) and A. poiformis (Schlechter, 1923: 164) Dudek &
Szlachetko (2010: 5). Only one is still treated as a true Elleanthus,
E. capitatus, though cited with a wrong authority: the basionym of the
species cited by Ames & Correll is Bletia capitata R. Brown (1813: 206) =
Elleanthus cephalotus Garay & H.R. Sweet (1972: 390), a species endemics to
West Indies. Finally we do not know which species represents the plant
listed in their book. Among the seven species listed by Dix & Dix (2000),
apart from the same “E. capitatus”, only two are true Elleanthus: E. caricoides
Nash (1907: 119) and E. hymenophorus (Reichenbach f., 1852: 710)
Reichenbach f. (1862: 480). Recently Archila & Chiron (2017) proposed two
Guatemalan new species, Elleantus asturiasii Archila & Chiron (2017: 149)
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and Elleanthus gelatinosus Archila & Chiron (2017: 152), both with lilas-
colored capitate flowers, who are now considered as members of the genus
Evelyna Rafinesque (1838: 164). Finally, only two Elleanthus species have
hitherto been found in Guatemala (Archila et al., in press). During one of
his botanical tours in Alta Verapaz, the senior author noticed an Elleanthus
plant leaves of which were intense purple on their abaxial face. It is
described below as a new species.
In Orchidaceae the rewards to pollinators are very diverse (Van der Cingel,
2001) and include nectar, resins, wax and other types of food, fragrances ...
and pseudocopulation, as in Lepanthes (Archila, 2001). However, the most
common reward is nectar, which is present in flowers of various
morphologies, adapted to various pollinators, insects such as Diptera
(flies), Hymenoptera (bees and wasps), Lepidoptera (butterflies), and birds
such asTrochilidae (colibris) in the New World (Neubig et al., 2015). It can
be observed that Elleanthus flowers are visited by colibris which pollinate
95-98% of their flowers; however it is suspected that the colibri, when
collecting the nectar, pushes with its beak the pollinia towards the stigma,
instead of transporting the pollinia from a flower to another one. It could
explain the high pollination rate. Besides, these observations can indicate
that the bird is attracted by the color of the flowers (orange), little variable
in the species of the genus, more than by the shape of the flowers. That is
why the morphology is very stable within a particular species. So the
morphological differences within the genus are considered as a strong
taxonomic basis to differentiate species.
Taxonomic treatment
Elleanthus C. Presl, Reliquiae Haenkeanae 1(2): 97. 1827.
TYPE: Elleanthus lancifolius C. Presl.
Epiphytic, terrestrial or lithophytic plants with no storage organs. Leaves
linear, lanceolate to elliptic-lanceolate, plicate, glabrous or pubescent.
Inflorescence terminal, usually densely few- to many-flowered, arranged
spirally or distichiously. Floral bracts prominent, imbricating, often
brightly coloured, yellow, orange to purple. Flowers small to medium,
erect, tubular, white, lemon-yellow, orange to deep purple. Tepals
dissimilar or subsimilar. Lateral sepals free or partially connate at the base.
Lip saccate and tubular at the base, more or less enclosing the
gynostemium, unlobed or obscurely 3-lobed, with fimbriate or dentate
A new Elleanthus from Guatemala – Archila & Chiron
margins, with a pair of large globose or subglobose calli. Gynostemium
slender. Anther terminal, erect. Pollinia 8, clavate to obovoid, laterally
compressed. Caudiculae sticky. Apical clinandrium obscure or rather
prominent. Stigma obtriangular to elliptic, deeply concave. Rostellum
shelf-like to ligulate, erect to subincumbent, truncate to rounded.
Viscidium single of various sizes, sometimes relatively large. Rostellum
remnant foveolate. (Archila et al., in press).
Elleanthus archilae Chiron & Tribouillier, sp. nov.
Type: Guatemala, Alta Verapaz, Cobán, collected by Fredy Archila en
Chamá Grande, 1000 m. s.n.m., XI/2009, FA-sn (holotype & isotype BIGU).
Etymology: dedicated to Fredy Archila Morales, who collected the type
specimen.
Haec herba Elleanthus hymenophorus (Reichenbach f.) Reichenbach f. similis est
sed foliis violaceis, bracteis acuminatis, sepalo intermedio triangulare-ovato acuto,
sepalis lateralibus oblongis, petalis lineare-ellipticis acutis, labello leviter incurvato
subquadrato, columna oblongo-ovata, ovario glabro, differt.
Plant medium-sized, thin; leaves elliptic, with a very strong apical
constriction, 10-18.7 cm long, 5-7 cm wide, purple on their abaxial face,
sheathing petiole corinthe glabrous; inflorescence with a basal bract elliptic
and wide; floral bracts short and acute, 0.5-1 cm long, 0.2-0.3 cm wide;
dorsal sepal triangular-ovate, apically acute, 0.55 cm long, 0.35 cm wide;
lateral sepals oblong, shortly mucronate, 0.55 cm long, 0.4 cm wide; petals
linear-elliptic, apically acute, 0.4 cm long, 0.1 cm wide; lip 0.75 cm long, 0.5
cm wide, divided into two parts, apical lamina subquadrate, basal part
saccate, with lateral projections obliquely orbicular and with two obliquely
oblong appendages inside; gynostemium 0.3 cm long, oblong-ovate; anther
totally covering the apical part of the gynostemium; ovary 0.4 cm long,
glabrous. Fig. 1.
Taxonomic notes. The closest relative of this new species is Elleanthus
hymenophorus (Fig. 2). However a number of differences allow to easily
distinguish them. In the latter the plants are large and robust, the leaves are
green, orbicular-eliptic, inconspicuously constricted, with a green
pubescent (scattered scaly pubescence) petiole, the inflorescence bract is
linear-oblong, the floral bracts long and acuminate, the dorsal sepal and the
petals oblong obtuse, the lateral sepals elliptic long-mucronate, the apical
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lamina of the lip orbicular, the lateral projections of the lip basal part are
not oblique, the gynostemium is oblong, the anther covers only 80% of the
gynostemium apex and the ovary is adorned with a scattered scaly
pubescence. See Fig. 3 & 4.
Fig. 1. Elleanthus archilae Fig. 2. Elleanthus hymenophorus
[drawings F. Archila]
Fig. 3. Elleanthus archilae Fig. 4. Elleanthus hymenophorus
[ph. F. Archila]
Conservation status. The species is threatened by the destruction of the
forests and by illegal collections. Especially as its characteristics can make it
a decorative plant.
A new Elleanthus from Guatemala – Archila & Chiron
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