Dendrobium petrophilum (Kraenzl.) Garay ex N. Hallé, a well-named species describing its unusual chasmophytic ecology Author Pignal, Marc Institut de Systématique, Évolution et Biodiversité, ISYEB – Muséum national d’Histoire naturelle, Centre national de la Recherche scientifique, Sorbonne Université, École pratique des Hautes Études, Université des Antilles, case postale 39, 57 rue Cuvier, F- 75231 Paris cedex 05 (France) pignal@mnhn.fr Author Laudereau, Christian Endemia, Plant Red List Authority, BP 4682, 98847 Nouméa (New Caledonia) (Attaché honoraire au Muséum national d’Histoire naturelle) Author Gâteblé, Gildas Institut Agronomique néo-Calédonien, Équipe ARBOREAL, BP 711, 98810 Mont-Dore (New Caledonia) Author Laudereau, Pierre-Louis Endemia, Plant Red List Authority, BP 4682, 98847 Nouméa (New Caledonia) text Adansonia 2022 3 2022-01-11 44 1 1 9 journal article 2559 10.5252/adansonia2022v44a1 248d7984-1f93-4514-b646-776c5c8238a8 1639-4798 5864969 Dendrobium oppositifolium (Kraenzl.) N.Hallé ( Figs 2E ; 3 F-J; 4 ) Flore de la Nouvelle-Calédonie & Dépendances 8: 119 ( Hallé 1977 ) . — Eria oppositifolia Kraenzl. , Vierteljahrsschrift der Naturforschenden Gesellschaft in Zürich 74: 90 ( Kränzlin 1929 ) . — Tetrodon oppositifolius (Kraenzl.) M.A.Clem.& D.L.Jones , Orchadian 12: 310 ( Clements & Jones 1998 ) . — Type: New Caledonia . Auf den Araucarien auf dem Plateau des Koniambo , Koné , [on the Araucaria on the Plateau de Koniambo], fl., 18.I.1925 , A.U. Däniker 894 (holo-, Z [ Z-000016413 ], image seen). Dendrobium multilobatum Guillaumin , Mémoires du Muséum national d’Histoire naturelle, série B, Botanique 8: 36 (1957) . — Type: New Caledonia . Bord de forêt de montagne près de la côte, 500 m de la route de la Mgne [ Montagne ] des Sources , fl., 29.XII.1950 , Hürlimann 468 (holo-, Z [ Z-000016357 ], image seen ; iso-, P [ P00121211 !] fragment). ETYMOLOGY. — The epithet refers to the leaves which are opposite. PHENOLOGY. — The species flowers mainly during the hottest season between October and March but from herbarium specimens, flowering has also been observed in July. Fruits have been recorded all the year (based on herbaria and field observations). ECOLOGY. — This species lives as an epiphyte on trees, usually in rainforests, forest edges and sometimes in more open vegetation conditions ( Araucaria spp. ) at higher altitudes. Most of the observations and specimens are from open or low forests ranging from 200 to 1200 m above sea level. Because Dendrobium oppositifolium seems to favour semi-shaded conditions, it has been rarely observed in dense rainforests where it might occur within the difficult to access canopy of the large and highest trees. CONSERVATION STATUS. — It is a common endemic species distributed from the South to the North of mainland Grande Terre and even on Île des Pins [Isle of Pines]. Even if some plants and populations are threatened by anthropogenic fires and by illegal removal (the species is protected in the Northern province) from plant and orchid hunters, the species is globally not threatened. It has been successfully cultivated in Paris museum greenhouses as well as by local orchid growers, but remains very difficult to maintain. We agree with the RLA Endemia assessment made on 29 January 2016 ( Butin et al. 2020b ) classifying the species as Least Concern (LC). ADDITIONAL MATERIAL EXAMINED. — New Caledonia . Province Nord , Ouégoa , Mandjélia , 780 m , forêt, 4.I.1978 , P.R.J. Bamps 6123 ( P [ P00115105 ]!). — Kone , Plateau de Kaniambo , Koné , 18.I.1925 , A.U. Däniker 894 ( P [ P02106271 ] photocopy with an additional drawing of the flower by N. Hallé!). — Ouégoa , Crête au Sud du Col d’Amos , 17.III.1966 , H.S. MacKee 14573 ( P [ P00115093 ]!). — Hienghène , Massif de Ton-Non : Roches Ouaième , 10.I.1968 , H.S. MacKee 18246 ( P [ P00115091 ]!). — Pouembout , Mt. Paéoua , 15.II.1968 , H.S. MacKee 18427 ( P [ P00115087 ]!). — Ouégoa , Haute Diahot : Tendé ( Expl. For. Frouin ), 500- 660 m , 12.III.1968 , H.S. MacKee 20003 ( NOU [ NOU003683 ]!; P [ P00115086 ]!). — Ouégoa , Pouébo :Crête entre Mandjélia / Salandané , 15.III.1969 , H.S. MacKee 21281 ( P [ P00115085 ]!). — Ouégoa , Pouébo : Mandjélia / Salandané , 26.II.1970 , H.S. MacKee 21630 ( P [ P00115083 ]!). — Poya , Ponérihouen : Contrefort E Mt. Aoupinié , 26.IV.1972 , H.S. MacKee 25330 ( P [ P00115097 ]!). — Poya , Pente S Mt. Boulinda , 30.VII.1973 , H.S. MacKee 27014 ( P [ P00115080 ]!). — Pouébo , Pouébo, 24.VII.1974 , H.S.MacKee 28970 ( P [ P00115104 ]!). — Hienghène , Panié , 12.I.1976 , H.S. MacKee 30664 ( P [ P00115079 ]!). — Poya , Ponérihouen : Crête sommet Mt. Aouipinié , 10.V.1976 , H.S. MacKee 31199 ( P [ P00115096 ]!). — Kaala-Gomen , Crête SW Mt. Taom , 13.VII.1979 , H.S. MacKee 37144 ( P [ P00115112 ]!). — Pouébo , Pouébo: Oumbarinien , 9.I.1981 , H.S. MacKee 38553 ( P [ P00115111 ]!). — Hienghène , Pente E Mt . Panié, 11.II.1981 , H.S. MacKee 38737 ( P [ P00115110 ]!). — Houaïlou , Bourail : Mé Jéjéhari , 5.II.1985 , H.S. MacKee 42444 ( P [ P00115114 ]!). — Mt Colnett : Versant Est , 800 m , forêt humide, Schistes , 2.II.2003 , A. Mouly , G. McPherson & U. Svenson 94 ( P [ P00591695 ]!). — Poindimié , Massif du Tchingou , face Est, 29.III.2001 , J. Munzinger 572 ( P [ P00239087 ]!). — Pouembout , Paéoua Mt 800-1100m, 1100 m , forêt à Nothofagus , 26.I.2010 , J. Munzinger 6021 ( NOU [ NOU053561 ]!). — Hienghène , Dawenia (zone), 929 m , 14.II.2010 , J. Munzinger et al. 6319 ( NOU [ NOU063498 ]!). — Hienghène , La Guen , cascade (Panié), 910 m , forêt basse, 23.II.2010 , J. Munzinger (Leg. Butin , J .- P .) 6468 ( NOU [ NOU063648 ]!). — Mt Panié , 500- 900m , 14.II.2006 , Y. Pillon 294 ( NOU [ NOU010843 ]!). — Mont Panié , forêt basse, 14.II.2006 , Y. Pillon , J. Munzinger , I. Spir & al. 9486 ( P [ P00684671 ]!). — Kaala-Gomen , Taom Mt (zone), 900 m , 24.III.1982 , B. Suprin 1731 ( NOU [ NOU003688 ]!). — Tipindjé : Mont Cantaloupaï (versant N), 16.IX.1983 , B. Suprin 2295 ( P [ P00115107 ]!). — Kouaoua : décharge Montmartre , 750 m , 14.II.1978 , J.-M. Veillon 3524 ( NOU [ NOU003684 ]!; P [ P00115109 ]!). — Houailou , Mt Menazi , crête vers 900 m versant nord, 6.VII.1989 , J.-M. Veillon 7075 ( NOU [ NOU003685 ]!). — Wagap , 1861-1867, E. Vieillard 3284 ( P [ P00115101 ]!). — Kaala-Gomen , près du sommet du Mont Kaala , 1000 m , 2.I.1943 , R. Virot 1402 ( P [ P00115098 ]!). — Province Sud : Sarraméa , Mé Améri , 700 m , 29.II.1950 , A. Guillaumin 8996 ( P [ P00115094 ]!). — Boulouparis , Mt Do (zone), sous-bois de forêt, 16.I.1982 , M. Hoff 4423 ( NOU [ NOU003687 ]!). — Bordure de forêt de montagne , près de la côte, 500 m de la route pour la Montagne des Sources , 29.III.1950 , H. Hürlimann 468 ( P [ P00121211 ]!). — Boulouparis , Mont Do , 13.IX.2019 , C. Laudereau 269 ( NOU [ NOU091401 ]!). — Païta , Dzumac , 13.IX.2019 , C. Laudereau 281 ( NOU [ NOU091400 ]!). — Yaté , Plateau de la Montagne des Sources , 31.III.1967 , H.S. MacKee 18200 ( P [ P00115092 ]!). — Bourail , Maoya Mé : contrefort S Djiaouma , 11.II.1970 , H.S. MacKee 21554 ( P [ P00115084 ]!). — Boulouparis , Plateau sommet Mt. Do , 26.I.1972 , H.S. MacKee 24898 ( P [ P00115082 ]!). — Bourail , 4 km à l’W Mé Aoui , 14.II.1976 , H.S. MacKee 32265 ( P [ P00115078 ]!). — Boulouparis , Mt. Do , 22.II.1976 , H.S. MacKee 32288 ( P [ P00115095 ]!). — Païta , Mt. Mou , 27.V.1979 , H.S. MacKee 36940 ( P [ P00115113 ]!). — Sarraméa , Col Amieu : Mt. Pembai , 1.III.1982 , H.S. MacKee 40302 ( P [ P00115115 ]!). — Along old lumber road to top of Mt Mé Ori , above Katrikoin , 900 m , 7.IX.1980 , G. McPherson 3054 ( P [ P00115106 ]!). — Thio , Mont Nakada , 18.IV.2001 , J. Munzinger 801 ( P [ P00217010 ]!). — Thio , Forêt de Sailles , 4.III.2001 , J. Munzinger 1194 ( P [ P00239729 ]!). — Yaté , Massif du Kouakoué , bassin de la Haute Ni, 950 m , 30.IV.2004 , M. Pignal , J. Munzinger et P. Lowry 2438 ( P [ P00465755 ]!). — Mont Do , c. 900-1000 m, en lisière de forêt, très souvent sur Araucaria laubenfelsii , 1020 m , 1.II.1972 , J.-M.Veillon 2511 ( NOU [ NOU003686 , NOU003686 ]!; P [ P00115102 , P00115103 , P00115108 ]!). — Mont-Dore , Haute Boulari camp no. 3, 500 m , V.1938 , R. Virot s.n. ( P [ P00115099 ]!). FIG. 4. — Distribution of Dendrobium oppositifolium (Kraenzl.) N.Hallé ( blue ) and D. petrophilum (Kraenzl.) Garay ex N.Hallé ( red ) in New Caledonia ( La Grande Terre and Île des Pins ): A , focus in the Poum area. Grey shaded areas represent ultramafic outcrops. Circles correspond to herbarium specimens while squares correspond to in situ observations from various authors and compiled by Endemia.nc. Tm , To and Tp represent respectively the type localities of D. multilobatum Guillaumin , D. oppositifolium and D. petrophilum names. DESCRIPTION Epiphytic plant. Pseudobulbs bifoliate, ovate to turbinate, 8-(20-28)-44 × 4-(6-8)- 25 mm , with 4-5 internodes, bright orange on dry material, covered with 3 deciduous, broad, papyraceous and translucent cataphylls applied to the pseudobulb. Leaf: gutter-shaped pseudopetiole canaliculate, 2-4 mm , blade coriaceous ovate to elliptic 16-(27-39)- 72 × 7-(10-13)- 27 mm , apex obtuse. Inflorescence, 80- (140-240)- 420 mm , with 2-(4-7)-18 flowers, sometimes once branched, flower non resupinate, borne in a subterminal position of the pseudobulb, more or less hanging. Flower: Peduncle, 10 × 0.9 mm . Tepals yellow to brownish green. Median sepal, linear lanceolate, 18.7 × 4 mm , 5 visible veins. Lateral sepals lanceolate, curved proximally, 16.5 × 4.6 mm . Petals spatulate, curved proximally, 17 × 4.3 mm . Lip, 3-lobed, 10 × 5 mm . Hypochile thick, warty, greenish-white, thickened in the centre, extended by 3 very divergent flattened extensions, white with dark pink stains, 2.2-2.3 mm long and 0.6 mm wide. Lateral lobes erect, 3.3 × 1.9 mm , longitudinally striated dark pink, white proximally and bright orange distally, ovate, with a very attenuated tooth on the side showing the proximal lobule of D. petrophilum . Median lobe 3-lobulate, curved, 6 × 5 mm , greenish-white in the centre with a triangular central verrucous crest. Lateral lobules, triangular, slightly deflected, 1 × 1.2 mm , dark pink with greenish-white tip, panduriform median lobule with rounded apex, curved at the tip making it appear emarginate, 5.8 × 6 mm , dark pink. Column white, except the edge of the stigma which is dark pink (protruding 1 mm down), 6 × 2.5 mm with a 4 mm long mentum, and 1.9 mm deep at the point of attachment to the ovary. Stamen: anther cap (connective appendage) white, 1.1 mm wide and 1.4 mm high. Pollinia, 2, yellow, obovoid, 0.9 mm long. Stigma rectangular 1.3 mm wide and 1.6 mm high. Ovary, 4.5 × 1.4 mm . Fruit obovoid, (16-)19-23(-26) × (5-)6-8(-10) mm. TABLE 1. — Comparaison des caractères morphologiques entre Dendrobium petrophilum (Kraenzl.) Garay ex N.Hallé et D. oppositifolium (Kraenzl.) N.Hallé. Les caractères indiqués par * sont basés sur plus de 600 mesures et sont présentés selon la convention (min-) quartile 1-quartile 3 (-max).
Dendrobium petrophilum Dendrobium oppositifolium
Écologie lithophyte/chasmophyte épiphyte
Pseudobulbe (mm)* (23-)32-40(-74) × (4-)6-8(-13) (8-)20-28(-44) × (4-)6-8(-25)
Limbe (mm)* (19-)26-41(-58) × (6-)8-10(-12) (16-)27-39(-72) × (7-)10-13(-27)
Inflorescences (mm)* plutôt dressées, plus ou moins retombantes,
(70-)260-320(-380) (80-)140-240(-420)
Fleurs/infl.* (9-)10-13(-21) (2-)4-7(-18)
Fleurs Tépales jaunes et labelle rose pâle bordé de blanc, Tépales jaunes et labelle rose soutenu, à lobes latéraux
lobes latéraux roses du labelle orangés
Tépales moins de 7 mm plus de 15 mm
Sépale médian lancéolé linéaire linéaire-lancéolé
Sépales latéraux peu recourbés à la base très recourbés à la base
Pétales peu recourbés à la base très recourbés à la base
Labelle c. 5 mm de long environ, c. 10 mm de long environ,
extensions peu divergentes de 1 mm de long, extensions très divergentes de plus de 2 mm de long,
mésochile à gibbosités de 0,7 mm d’épaisseur, mésochile verruqueux,
lobe médian trilobulé de moins de 2,5 mm de longueur lobe médian panduriforme de plus de 5 mm de longueur
Stigmate rectangulaire à ouverture à peu près aussi haute que rectangulaire à ouverture manifestement plus haute que
large, bordé de rose pâle large, bordé de rose foncé
Fruit* (mm) obovoïde à sphérique, (13-)13-15(-17) × (7-)8-10, obovoïde, (16-)19-23(-26) × (5-)6-8(-10), verdâtre
verdâtre avec des bandes violettes
TABLE 2. — Comparison of morphological characters between Dendrobium petrophilum (Kraenzl.) Garay ex N.Hallé and D. oppositifolium (Kraenzl.) N.Hallé. Characters indicated by * are based on more than 600 measurements and are presented as (min-) quartile 1-quartile 3 (-max).
Dendrobium petrophilum Dendrobium oppositifolium
Ecology lithophytic/chasmophytic epiphytic
Pseudobulb (mm)* (23-)32-40(-74) × (4-)6-8(-13) (8-)20-28(-44) × (4-)6-8(-25)
Leaf blade (mm)* (19-)26-41(-58) × (6-)8-10(-12) (16-)27-39(-72) × (7-)10-13(-27)
Inflorescences (mm)* rather erect, more or less falling down,
(70-)260-320(-380) (80-)140-240(-420)
Flowers/infl* (9-)10-13(-21) (2-)4-7(-18)
Flowers tepals yellow and lip pale pink edged with white; tepals yellow and lip dark pink; lateral lobes orange
lateral lobes pink
Tepals less than 7 mm more than 15 mm
Median sepal lanceolate linear lanceolate
Lateral sepals slightly curved at the base strongly curved at the base
Petals slightly curved at the base strongly curved at the base
Lip c. 5 mm long, slightly divergent extensions of 1 mm c. 10 mm long, very divergent extensions of more
in length, mesochile with gibbosity of 0.7 mm thick, than 2 mm in length, mesochile warty, median lobe
median lobe trilobular, less than 2.5 mm long panduriform more than 5 mm long
Stigma rectangular with an opening about as high as it is rectangular with an opening that is clearly higher than
wide, edged with pale pink wide, bordered with dark pink
Fruit* (mm) obovoid to spherical greenish with purple obovoid, greenish
strips (13-)13-15(-17) × (7-)8-10 (16-)19-23(-26) × (5-)6-8(-10)
The vegetative system of the two species is very similar. However, the flowers as well as fruits have notable differences in size, shape and colour as summarised in Tables 1 and 2 .