Dendrobium dangioanum M.Pignal, 2023

Pignal, Marc, 2023, Two new species of Dendrobium Sw. from New Caledonia in the section Macrocladium Schltr. and a note about Dendrobium kanakorum Kraenzl., Adansonia (3) 45 (25), pp. 385-393 : 390

Dendrobium dangioanum M.Pignal , sp. nov.

( Figs 1B , 2 ; Table 1 )

Dendrobio finetiano Finet similis , sed floribus largioribus (16 mm vs 9 mm), labello atrovinoso (vs roseum albumque), lobo mediano labelli longiore (2.8 vs 1.5 mm), praecipue differt.

TYPUS. — Nouvelle-Calédonie. Province Nord, La Foa, Parc des Grandes Fougères , 21°36’38”S, 165°45’16”E, 20. I.2019, fl., C. Laudereau 1251 (holo-, NOU [ NOU092609 ]!; iso-, P [ P02275933 ]!).

PARATYPI. — Nouvelle-Calédonie. Province Nord, Poindimié, Amoa GR Pombei, 20°56’17”S, 165°11’35”E, 25.XI.2016, fl., C. Laudereau & P.-L. Laudereau 156 ( NOU [ NOU092608 ]!, P [ P02275936 ]!); Poindimié, Pic Amoa, 22°14’48”S, 166°49’35”E, 4.IV.2017 fl., C. Laudereau & P.-L. Laudereau 411 ( NOU [ NOU092607 ]!); Poindimié, Amoa GR Pombei, 20°56’17”S, 165°11’35”E, 7.VIII.2017, fl., C. Laudereau & P.-L. Laudereau 513 ( NOU [ NOU092606 ]!); Haute Tchamba: Expl. For. Létocart, forêt humide, 500 m, [21°1’12”S, 165°13’47”E], fl., 21.XII.1967, H.S. MacKee 17999 ( P [ P00118597 ]!); Haute Tiwaka: Contrefort Est du Tchingou, maquis dégradé, Reste de forêt humide, terrain serpentineux, 800 m, [20°54’31”S, 165°1’7”E], 6. I.1969, fl., H.S. MacKee 20130 ( NOU [ NOU002536 ] image!, P [ P00118588 ]!); Mont Boulinda , ravin face N, 800 m, [21°14’12”S, 165°7’31”E], 9.XII.1970, fl., J.-M. Veillon 2228 ( P [ P00118573 ]!). — Province Sud, Sarraméa, Plateau de Dogny , 21°36’51”S, 165°52’30”E, 25.II.2017, fl., C. Laudereau & P.-L. Laudereau 344 ( NOU [ NOU092605 ]!, P [ P02275934 ]!); La Foa, Ouipoin, 21°41’10”S, 165°59’02”E, fl., 14.XII.2018, C. Laudereau 1237 ( NOU [ NOU092604 ]!); Plateau de Dogny , 900-1000 m, [21°37’24”S, 165°52’41”E], 18. I.1961, fl., H.S. MacKee 8190 ( P [ P00112236 ]!); Farino: Forêt Mépéou, 500 m, [21°37’5”S, 165°46’35”E], 25. V.1965, fl. H.S. MacKee 12678 ( P [ P00118602 ]!); Col d’Amieu: Mt. Pembaï , forêt humide, schistes, 800 m, [21°35’20”S, 165°50’30”E], 15.IV.1976, fl. H.S. MacKee 31056 ( P [ P00118589 ]!). — Without precise locality: s.l., 25.IV.1975, fl, J. Hoock 50 (P[P00118605]!).

ETYMOLOGY. — This new species is dedicated to Jacques D’Angio, plant enthusiast, and especially of orchids, who was involved in the fight against invasive animals in the Parc Provincial des Grandes Fougères (Grandes Fougères Provincial Park) and in particular the protection of its “royal ferns”.

PHENOLOGY. — The taxon has been observed in flower from October to August. Flower remain at anthesis for c. 7 days (C. Laudereau, pers. com.).

HABITAT AND DISTRIBUTION. — Dendrobium dangioanum sp. nov. is found in the central regions of New Caledonia. It grows between 300 and 1000 m altitude in wet forest or degraded maquis. It is difficult to differentiate from D. finetianum in the vegetative state. CONSERVATION STATUS. — The species, like all other members of Orchidaceae , is protected in the Northern Province.

DESCRIPTION

Epiphyte with erect, close-spaced stems, with a slightly swollen basal internode. Rhizome short and flexuous, branching sympodial. Stem flexuose, (207-)238-315(-388) × (1,4-)1,7-2(-4) mm, bearing (6-)14-18(-23) leaves, often leafless at the base. Internodes of (11-)13-18(-23) mm. Slightly overlapping sheaths of the same length as the internodes. Leaf blade lanceolate, (28-)34-48(-66) × (4-)5-8(-10) mm with a slightly asymmetrical apex. Inflorescences, 1-4, in axillary and subterminal racemes, sometimes bifid, (23-)29- 46(-173) mm, borne at the base of the sheaths to which they are axillary, making them appear opposite the next-most proximal leaf, sometimes on defoliated stems (sheaths persistent), each bearing (6-)10-11(-13) flowers. Flowers resupinate. Bracts c. 2 mm, triangular. Pedicel straight, c. 25 mm long. Tepals yellow with irregular red streaks, texture glossy with edge curling back with age. Dorsal sepal narrowly ovate to lanceolate, 9-9.5 × 3 mm. Lateral sepals asymmetrical, ovate, 8.2 × 3 mm. Petals obovate to spatulate, 10 × 3.4 mm. Mentum white, 2 × 1.5 mm and 0.6 mm deep, furrowed. Labellum, 7-8 × 4 mm, 3-lobed. Lateral lobes upright, roughly triangular, 2.8 mm long and 1.6 mm high, white, longitudinally streaked with burgundy red on the lower half. Callus white yellowish. Median lobe ovate, 4.8 × 4.2 mm, burgundy red except for a spot at the distal 1 mm and the tips of the lobules which are white, lateral lobules rectangular, 1.6 × 0.7 mm, median lobule tuberculate in the centre and with a strongly wavy margin and inwardly folded apex. Column, 2.3 × 1.6 mm and c. 0.9 mm deep, white, furrowed ventrally, with dark pink macules on the sides of the stigmatic orifice, very pubescent on the edges of the furrow. Lateral staminodes white. Stigmatic cavity, 0.7 × 0.8 mm wide. Connective pink, 0.9 mm wide × 0.8 mm high and 0.7 mm deep. Pollinia obovoid, dark yellow, 0.6 × 0.25 mm. Ovary 2.5 × 0.8 mm, slightly curved. Capsule fusiform, obovoid, green, 14 × 5 mm, borne on an 8 mm pedicel.

Figures

FIG. 1. — A, Dendrobium laudereavorum M. Pignal, sp. nov.; B, D. dangioanum M. Pignal, sp. nov.; C, D. finetianum Schltr. Abbreviations: f, flower; lf, labellum face; lp, labellum profile. Photos: C. Laudereau. Scale bars: f, 10 mm; lf, lp, 3 mm.

FIG. 2. — Distribution of members of the Dendrobium finetianum group: D. finetianum Schltr. (blue dots), D. dangioanum M. Pignal, sp. nov. (red dots), D. laudereavorum M. Pignal,sp. nov. (green dot) (undifferentiated ocean and geological units [white], ultrabasic rocks [grey], protected areas [dotted line]). A dynamic version of the map is available here: http://u.osmfr.org/m/955223/