Dendrobium letocartiorum Munzinger & M.Pignal, 2020

Pignal, Marc & Munzinger, Jérôme, 2020, Morphological and anatomical investigation of New Caledonian graminoid Dendrobium (Orchidaceae) with the description of two new species, European Journal of Taxonomy 633, pp. 1-26 : 17-21

publication ID

https://doi.org/ 10.5852/ejt.2020.633

DOI

https://doi.org/10.5281/zenodo.3803522

persistent identifier

https://treatment.plazi.org/id/03A887CA-FF9F-FFBA-FE3C-550D646DFB50

treatment provided by

Valdenar

scientific name

Dendrobium letocartiorum Munzinger & M.Pignal
status

sp. nov.

Dendrobium letocartiorum Munzinger & M.Pignal View in CoL , sp. nov.

urn:lsid:ipni.org:names:77209476-1

Figs 1 View Fig C–D, F–G, T, 3 View Fig E–G, 4 View Fig Ba, 5 View Fig G, 10 View Fig , 11 View Fig

Diagnosis

Dendrobium bilobo Lindl. affinis , sed foliorum rostratis vaginis (versus truncatas), sine atropurpureis maculis labello, dorsali sepalo triangulari, 12 × 2 mm (versus ovatum 4–5 × 2–3 mm), lateralibus sepalis 12 × 4 mm (versus 6. 5 × 4. 5 mm), petalis linearis vel paulo lanceolata, 11 × ca 1 mm (vs lanceolata, 3. 5–4 × 1. 5–2 mm), gynostegio cum atropurpureis faciali interni maculis (vs pallide purpureis aut albis), praecipue differt.

Etymology

The species is dedicated to our friends Irène and Daniel Létocart who collected and cultivated this plant in 1978–1980, providing H.S. MacKee with material for the first herbarium specimens, and also to the Létocart family, whose many members are active naturalists, creators of the Endemia website, and with whom we have made many field trips.

Type material

NEW CALEDONIA – Province Nord • Mont Colnett, versant Est; 20°29′13″ S, 164°42′39″ E; alt. 700 m; border zone between the altitude rainforest and the savanna of burns, schists; 3 Nov. 2003; fl. & fr.; Mouly 99; holotype: P [ P00777176 ]!; isotypes: P [ P00777177 ]!, NOU [ NOU090448 About NOU !]. – Dendrobium crassifomentum Hallé ined. in herb GoogleMaps .

Paratypes

NEW CALEDONIA – Province Nord • Mont Colnett ; alt. 720 m; 29 Oct. 2003; fl.; Butin s.n.; P [ P00352883 ] Mont Colnett ; 20°29′17″ S, 164°42′43″ E; alt. 720 m; 10 May 2003; fl.; Butin s.n.; P [ P00493892 ] GoogleMaps Mont Mandjelia , Pouébo, 20°23′51″ S, 164°31′57″ E; 10 Dec. 2016; C. Laudereau 98; NOU [ NOU090376 About NOU ] GoogleMaps Mont Mandjelia, Pouébo , 20°23′51″ S, 164°31′57″ E; 23 Dec. 2016; C. Laudereau 21 3; NOU [ NOU090375 About NOU ] GoogleMaps Colnett Oua Ina, Pouébo , 20°30′35″ S, 164°43′56″ E; 5 Jan. 2017; C. Laudereau 239; NOU [ NOU090374 About NOU ] GoogleMaps Pouébo, Mont Mandjélia ; 20°23′51″ S, 164°31′57″ E; 24 Oct. 2018; C. Laudereau 1155; NOU [ NOU090373 About NOU ] GoogleMaps Mont Mandjélia ; [20°24′2″ S, 164°31′41″ E]; 29 Sep. 1978; H.S. MacKee 35761 (leg. D. Létocart); P [ P00118401 ] GoogleMaps Tchamba ; [21°1′22″ S, 165°13′36″ E]; 21 Dec. 1978; H.S. MacKee 36261 (leg. D. Létocart); P [ P00118403 ] GoogleMaps Haute Diahot: Tendé ; [20°24′28″ S, 164°31′17″ E]; alt. 700 m; humid forest, micaschists; 12 Dec. 1979; H.S. MacKee 37117; P [ P00118404 ] GoogleMaps Pouébo, Mont Mandjélia ; [20°24′2″ S, 164°31′41″ E]; alt. 750 m; humid forest, schists; 26 Jan. 1980; H.S. MacKee 37760 (leg. Bégaud); P [ P00118405 ] GoogleMaps Pouébo, Mont Mandjélia ; [20°24′2″ S, 164°31′41″ E]; alt. 750 m; 14 Mar. 1980; H.S. MacKee 37908 (leg. D. Létocart); P [ P00118402 ] GoogleMaps ibid.; 20 Dec. 1980; H.S. MacKee 38198 (leg. D. Létocart); P [ P00118406 ] GoogleMaps Roches Ouaième ; alt. 950 m; 14 Jun. 2005, J. Munzinger 2915, Y. Pillon & J.-P. Butin; NOU [ NOU007988 About NOU ] Mandjélia ; 2 Dec. 2006; bt. fr.; J. Munzinger 4016, D. Létocart, I. Létocart, R. Amice & O. Chapelle; NOU [ NOU017301 About NOU ] Mont Panié ; [20°37′27″ S, 164°46′56″ E]; J. Munzinger 4326, H. Blaffart, M. Wanguene, O. Chapelle & J. Tiavouane; NOU [ NOU018878 ] GoogleMaps Dawenia, west buttress of Colnett ; 20°32′15″ S, 164°41′39″ E; 14 Nov. 2010; J. Munzinger 6290, Ph. Birnbaum, M. Callmander, I. Pounds, J.-P. Butin & H. Vandrot; NOU [ NOU063469 About NOU ]. GoogleMaps Province Sud • Col d’Amieu: Mt. Pembai ; [21°35′20″ S, 165°50′30″ E]; alt. 800 m; humid forest, schists; 15 Apr. 1976; fr.; H.S. MacKee 31229 (leg. Bégaud); P [ P00118400 ] GoogleMaps .

Description

Erect epiphyte. Roots whitish, ca 1–2 mm wide, at the base of the plant (axillary roots lacking). Stems reaching 60 cm long, slightly flattened, completely covered by the sheaths of the old leaves, lamina remaining only in the upper half, yellow-orange on dry material. Internodes ca 25 mm long at the base of the stem. Leaves spirally arranged, dark shiny green above, light green below (fide collectors’ notes), ca 75 × 7 mm. Midrib impressed on adaxial surface, very prominent on abaxial surface. Two lateral nerves very conspicuous, <1–2 mm from the margin (see discussion of anatomy below), numerous prominent smaller nerves visible, all convergent at the apex. Base narrow, forming a flattened pseudopetiole. Extremity emarginate, asymmetrical, the two lobes often diverging. Sheath striated in its upper half and ending in a beak opposite to the lamina and applied on the stem. Inflorescence 1-flowered, emerging through a slit of the foliar sheath. Pedicel 3.5 mm long. Ovary ca 3 mm long, non-resupinate. Bract acuminate, 2–3 mm long. Flower pale green to yellow, ca 12 mm long. Dorsal sepal triangular, 12 × 2 mm. Lateral sepals triangular, 12 × 4 mm at the base, with 7 nerves. Petals linear or slightly lanceolate, 11 × ca 1 mm. Lip entire, red, approximately elliptic, margin thin and undulate, 10 mm long and 3 mm wide, obscurely tricarinated. Mentum, 3 mm long. Column, 2.5 mm high and 2 mm wide with a fimbriate margin. Fruits very few despite an abundant flowering, yellow-greenish to brown when mature, ovoid, 8 mm in diameter, with base slightly narrower. Bracts persistent. Dried seed with transparent testa, ca 267 × 86 μm, fusiform, with extremity slender and base truncate, extremity strongly spiraled. Hydrated seed ovate, sacciform. Cells cubic or with extremities rounded, elongate, ca 43–110 × 7.3–10.2 μm, with thick edges, spiral orientation and smooth cellular walls. Embryo spherical elongate, ca 6–7 μm wide, inserted in the lower ¾ of the testa.

Taxonomic notes

Dendrobium letocartiorum sp. nov. has always slightly flattened stems. The species has affinities with D. bilobum Lindl. , but the flower is bigger and the lip does not have a dark red spot on the adaxial surface. Leaf anatomy shows that D. letocartiorum sp. nov. is very similar to D. camaridiorum , having thin leaves, 24–28 vascular bundles in one line and largest bundle in position 5(–6). They only differ by the margins in transverse section, which are obtuse in D. letocartiorum sp. nov. and truncate in D. camaridiorum ( Fig. 4B View Fig ).

Phenology

Flowering and fructification periods need further observations. The fruits were observed in the field and in cultivation (in New Caledonia) during the months of January, May, July, October, November and December and flowering specimens are from May and November.

Distribution and ecology

This endemic species occurs on the main island, in the central chain and on the Panié range in North-East coast. It grows on edges of humid forest, and also on rocks as a lithophyte and is known from 700–800 m a.s.l. The species has been observed also in Plateau de Dogny (Sarraméa) (C. Laudereau, pers. comm.)

IUCN status

This species is currently known from only four locations in New Caledonia, based on herbarium specimens. Dendrobium letocartiorum sp. nov. was evaluated as Near Threatened (NT) by the New Caledonian Red List Authority, considering the species apparent rarity and the low threat to its habitat.

P

Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants

NOU

Institut de Recherche pour le Développement

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