Ponthieva luegii (Orchidaceae), a new taxon from the karst formations of Guatemala3 Fredy Archila Morales1'2, Dariusz L. Szlachetko3, Guy R. Chiron4& Osmin Jared Vâsquez5 Keywords/Mots-clés/Palabras clave : Cranichideae, Guatemala, Humid Arc/Arc humide/Arco humedo, karst, Orchidaceae. Abstract A new species of lithophytic orchid, belonging to Ponthieva R.Brown, is described, illustrated and compared to Ponthieva ephippium Reichenbach f., its closest relative. This species is associate to the exposed karstic rocks which can be observed along the northern humid arc of Guatemala, a mountain complex with a karstic géologie base favouring high biodiversity. This particular habitat is described in detail. Résumé Ponthieva luegii (Orchidaceae), un nouveau taxon du paysage karstique guatémaltèque - Une nouvelle espèce d'orchidée lithophyte appartenant au genre Ponthieva est décrite, illustrée et comparée à l'espèce la plus proche, Ponthieva ephippium Reichenbach f. Elle est associée aux roches karstiques exposées qui se rencontrent le long de l'arc humide nord du Guatemala, complexe montagneux ayant une base géologique karstique, favorisant une grande biodiversité. Cet habitat particulier est ici présenté en détail. Resumen Ponthieva luegii, un nuevo registro del paisaje kârstico cobanero - Una nueva especie de orquidea litophytica es propuesta, asociada a rocas kârsticas expuestas, estas se encuentran creciendo en el arco humedo norte de Guatemala, un complejo montanoso caracterizado por ser una zona que a : manuscrit reçu le 12 février 2015, accepté le 18 mars 2015 article mis en ligne sur www.richardiana.com le 20/03/2015 - pp. 224-231 - © Tropicalia ISSN 1626-3596 (imp.) - 2262-9017 (élect.) 224 Richardiana XV - mars 2015 Ponthieva luegii, a new taxon from Guatemala - Archila et al. tiene como base geologica el karst pro ademâs un enorme riqueza en biodiversidad. La nueva especie perteneciente al género Ponthieva es descrita e ilustrada junto con la descripciôn de su habitat. Introduction The orchid tribe Cranichideae Endlicher comprises terrestrial, lithophytic, and rarely epiphytic plants. The fleshy roots are verticillate or produced along either a thick and fleshy rhizome or a tuber. The leaves are convolute, not plicate, fleshy, spirally arranged, either in a basal rosette or along the erect part of the stem. The inflorescence is terminal, erect, racemose, with one to many flowers, often pubescent or glandular. The floral bracts are persistent. The flowers are resupinate or rarely non resupinate, usually small, often somewhat tubular and not fully open. The sepals are usually subsimilar, the latéral ones often somewhat oblique at base. The petals are generally thinner than the sepals, often adnate to the dorsal sepal, forming a cap (Pridgeon et al, 2003). Within this tribe the best known group is the subtribe Cranichidinae Lindley comprising eight (Szlachetko & Rutkowski, 2000) or 9 (Dressler, 1993) généra and forming a monophyletic group (Salazar et al., 2003). Ponthieva R.Brown belongs to this subtribe and comprises 62 species (WCSP, 2015) that are sympodial and terrestrial or lithophytic. They can be observed at low to high altitudes, on hills or in mountain rain forests, forests with Sphagmum, and thickets, in the entire Neotropics, from Southern United States to Bolivia and Argentina (Alrich & Higgins, 2008). The gynostemium is usually short, erect, rather massive, often apically inflated, with the column part shorter than the anther, lacking a foot; the base of the anther is placed below the base of the stigma, the anther is erect, oblong or ovate, mobile, 2-cleft, the two parts parallel; the filament is entire or fused to the column for its greater part; the connective is short but very thick, often enlarged at the apex. The 4 pollinia are ovoid to oblong-ovoid, compact ; the caudicles are inconspicuous, made of the thin pollinia apex. The staminodes are united to the filament and the style and/or the base of the stigma, forming a prominent dorsal clinandrium, generally thick, massive and spacious. The stigma is horizontal to subventral, obscurely3- lobed, confluent, ovate or elliptic (Szlachetko & Rutkowski, 2000). XV - mars 2015 Richardiana 225 Ponthieva luegii, a new taxon from Guatemala - Archila et al. Seven species hâve been registered for Guatemala in the middle of the previous century (Ames & Correll, 1953-1954) and eleven in the most recent lists (Archila, 2014). A new one has been discovered by the senior author in the Department of Alta Verapaz. It forms a few populations growing on karstic rocks and comprising 10 to 50 individuals each, on a area of 200 m2. It is described and illustrated in this article. The orchid tribe Cranichideae Endlicher comprises terrestrial, lithophytic, rarely epiphytic plants; the fleshy roots are verticillate or produced along either a thick and fleshy rhizome or a tuber; the leaves are convolute, not plicate, fleshy, spirally arranged, either in a basal rosette or along the erect part of the stem; the inflorescence is terminal, erected, racemose, with one to many flowers, often pubescent or glandular; the floral bracts are persistent; the flowers are resupinate or rarely non resupinate, usually small, often somewhat tubular and not fully open; the sepals are usually subsimilar, the latéral ones often somewhat oblique at base; the petals are generally thinner than the sepals, often adnate to the dorsal sepal, forming a cap (Pridgeon et al., 2003). Within this tribe the best known group is the subtribe Cranichidinae Lindley comprising eight (Szlachetko & Rutkowski, 2000) or 9 (Dressler, 1993) généra and forming a monophyletic groupo (Salazar et al., 2003). Ponthieva R.Brown belongs to this subtribe and comprises 62 species (WCSP, 2015) that are sympodial and terrestrial or lithophytic; they can be observed t low to high altitudes, on hills or in mountain rain forests, forests with Sphagmum, and thickets, in the entire Neotropics, from Southern United States to Bolivia and Argentina (Alrich & Higgins, 2008). The gynostemium is usually short, erect, rather massive, often apically inflated, with the column part shorter than the anther, lacking foot; the anther base is placed below the srigma base, the anther is erect, oblong or ovate, mobile, 2-cleft, the two parts parallel; the filament is entire or fused to the column for its greater part; the connective is short but very thick, often enlarged at the apex, the 4 pollinia are ovoid to oblong-ovoid, compact ; the caudicles are inconspicuous, made of the thin pollinia apex ; the staminodes are united to the filament and the style and/or the base of the stigma, forming a prominent dorsal clinandrium, generally thick, massive and spacious ; the stigma is horizontal to subventral, obscurely3- lobed, confluent, ovate or elliptic (Szlachetko & Rutkowski, 2000). 226 Richardiana XV - mars 2015 Ponthieva luegii, a new taxon from Guatemala - Archila et al. Seven species hâve been registered for Guatemala in the middle of the previous century (Ames & Correll, 1953-1954) and eleven in the most recent lists (Archila, 2014). A new one has been discovered by the senior author in the Department of Alta Verapaz. It forms a few populations growing on karstic rocks and comprising 10 to 50 individuals each, on a area of 200 m2. It is described and illustrated in this article. Ponthieva luegii Archila, Szlachetko & Chiron, sp. nov. Fig. 1 & 2 Herba lithophyta nana, glabra cumfructo verrucoso. Flos alba roseomaculata. Haec herba Ponthieva ephippium Rchb. f. similis est sed inflorescencia bracteis floribusque glabris, floribus minoribus, adaxiale secus nervuram medianam roseomaculatis, bracteis floralibus brevis, fructis verrucosis, petalis divergentibus (versus parallelis) apice elongatis obtusisque (versus curtis orbicularïbusque), petalorum limborum lobo orbiculare (versus oblique obtuso), sepalis lateralibus oblique ellipticis (versus ovatis), differt. Type: Guatemala, Alta Verapaz, Se Quib, colectado por Fredy Archila, Francisco Archila, Javier Archila y Oscar Rodrigo Archila sobre rocas karsticas, Diciembre 2014, FA-sn (HT: BIGU). Etymology: the new entity is dedicated to Christian Lueg, a German grower of terrestrial orchids, for his important help with his plants in the study of the genus Cypripedium. Plant small; leaves elliptic, 3 cm long, 1.3 cm wide, apically acute; inflorescence 6 cm long producing 3-6 flowers; flower glabrous, white with a pink mark on the dorsal face of the sepals, along the central nerve, lip with a yellow spot on the base and a green mark on the latéral lobes, both marks reminding of a flying bird; floral bracts 2 mm long, glabrous; pedicel ovary 4.5 mm long; dorsal sepal obovate, 4.1 mm long, 2.1 mm wide, apically obtuse; latéral sepals ovate, oblique, 4.8 mm long, 4.2 mm wide, apically acute; petals 3.7 mm long, 1.9 mm wide, obliquely dolabriform with the ventral margin orbicular, the base obliquely linear, the séparation zone between the ventral part and the base folded, divergent and not United to the dorsal sepal, apically acute; labellum 3-lobed after a trapezoid base, latéral lobes 1.3 mm long and wide, orbicular, somewhat truncate at the base, apical lobe linear, 1.3 mm long, 0.4 mm wide, apically acuminate; column 2.7 mm long, obliquely oblong, stigma rounded, inserted into a XV - mars 2015 Richardiana 227 Ponthieva luegii, a new taxon from Guatemala - Archila et al, Fig. 1: Ponthieva luegii a: plant - b: dorsal sepal - c: latéral sepal - d: petal - e: labellum - f: column (drawing: F.Archila) Fig. 2: Ponthieva luegii (ph. F.Archila) 228 Richardiana XV - mars 2015 Ponthieva luegii, a new taxon from Guatemala - Archila et al. thick oblique cavity, rostellum apically recurved, anther elliptique, with an elliptic and swollen connective; fruit obovate, 9 mm long, 3.3 mm wide, irregularly papullose verrucose, seed very small, ovate oblong and oblique, dull brown (Fig. 3). Fig. 3: fruit [a] and seeds [b] of Ponthieva luegii (drawing : F.Archila) Discussion: this species is closely related to Ponthieva ephippium Reichenbach f. (of which a good drawing is provided by Hamer, 1985) from which it can be distinguished by its smaller flowers with pink stain along the central nerve on the dorsal face of the sepals, its short floral bracts, its glabrous inflorescence, flowers and bracts, its verrucose fruits, its divergent petals (parallel in P. ephippium), the form of the petal ventral lobe (orbicular in P. luegii, oblically obtuse in P. ephippium), its petal apex elongate and obtuse (versus short and orbicular in P. ephippium) and its latéral sepals obliquely elliptic (versus ovate). Habitat: plant growing in cracks on karstic rocks. The régional géologie frame of Guatemala is compound of various terrains which are the resuit of a particular géologie history. Guatemala is located between three tectonic plates (North American Plate, Caribbean Plate, Cocos Plate) whose margins are, ail in ail, made of igneous volcanic rocks in the South, metamorphic rocks in the Centre, and large sequences of sedimentary chalky rocks in the XV - mars 2015 Richardiana 229 Ponthieva luegii, a new taxon from Guatemala - Archila et ai North. The chalky rocks, mainly made of calcite (CaC03), constitute about 50% of the national land and resuit from Chemical sédimentation processes that occurred in the deep sea during various géologie times from the Paleozoic to the Tertiary era. Two of these formations, specially important because of their large dimensions, are the Chôchal formation and the Cobân formation. The former is a sequence of chalky rocks arranged in a superficial reef platform build during the late Paleozoic whereas the latter covers a large part of the northern Guatemala and is made of chalky rocks formed during the Cretaceous period arranged in a superficial carbonaceous platform. These carbonate formations, specially the Cretaceous chalky rocks, show an important karstic development. This name refers to a relief type which is the resuit of the dissolving of the chalky rocks due to the slow action of the weak acids présent in water. These acids are formed from the carbon dioxide coming from atmosphère or produced by plants and bacteria: C02 + H20 — H2C03. Calcite is dissolved producing Calcium bicarbonate, which is water-soluble and easily removed from the rock: H2C03 + CaC03 — CaHC03 + H20. As with many chimical processes, the reaction speed increase with the température and, in spite of the fact that the quantity of Carbon dioxide in solution is greater when température is lower, dissolution is more intense in tropical régions due to the greater quantity of biogenic Carbon dioxide. Because of these factors and because the chalky rocks are the soluble rocks more commun in the North of the country, the karstic process is présent in nearly ail the northern area independently of the local particuler climatic conditions. The superficial karst, or exokarst, includes terrain forms as diverse as dolinas (dépréssions formed by subsidence), sumideros or drains (vertical holes originated from collapse and locally referred to as siwanes), rivers desappearing and reappearing, conical karst and tower karst. The subterranean karst, or endokarst, is made of a network of subterranean cavities forming a well developped System, creating many caves of various sizes. Other relief forms, referred to as karren or lapiaz, appear as small furrows dug on the rock by dissolving or érosion processes. These furrows are usually between some millimeters to some centimeters deep. In the development of the karstic formations, some corrélation is observed, mainly between the density and form of the dolinas and caves and the geological structures of the terrain. Distribution and form of the caves, for example, generally agréé with the fault orientation whereas their abundance is generally associated with terrains with rather strong slopes. 230 Richardiana XV - mars 2015 Ponthieva luegii, a new taxon from Guatemala - Archila et al. References Alrich, P. & W.Higgins, 2008. Illustrated Dictionary of Orchid Généra. Selby Botanical Gardens Press, Sarasota. 482 pp. Ames, O. & D.Correll, 1953-1954. Orchids of Guatemala and Belize. Ed. 1985. Dover Publications, New York. 779 pp. Archila, F., 2014. Listado de Orquideas de Guatemala. Guatemalensis ano 17 (2). Dressler, R.L., 1993. Phylogeny and Classification of the Orchid Family. Dioscoride Press, Ortland. 314 pp. Hamer, F., 1985. Icônes Plantarum Tropicarum 12. Orchids pf Nicaragua: pl. 1261. The Mary Selby Botanical Gardens, Sarasota. Pridgeon, A., P.Cribb, M.W.Chase & F.N.Rasmussen, 2003. Généra Orchidacearum Volume 3: Orchidoideae (part 2), Vanilloideae. Oxford University Press, New York. 360 pp. Salazar, G.A., M.W.Chase, A.A. Soto Arenas & M.Ingrouille, 2003. Phylogenetics of Cranichideae with emphasis on Spiranthinae (Orchidaceae, Orchidoideae): evidence from plastid and nuclear DNA sequences .American Journal ofBoyany 90(5): 777-795. Szlachetko, D. & P.Rutkowski, 2002. Gynostemia Orchidalium I. Acta Botanica Fennica 169. 380 pp. WCSP, 2015. World Checklist of Selected Plant Families. Faciliatated by the Royal Botanic Gardens, Kew. Published on the Internet: http://apps.kew.org/wcsp/ Retrieved 12/02/2015. 1 : Estacion Experimental de orquideas de Guatemala - [email protected] 2 : Herbario BIGU, Universidad de San Carlos de Guatemala 3 : Department of Plant Taxonomy & Nature Conservation, The University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland 4 : Herbiers, Université de Lyon 1, F-69622 Villeurbanne Cedex (France) 5 : Facultad de Geologia, CUNOR, USAC XV - mars 2015 Richardiana 231