Dendrobium laudereavorum 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 : 391

Dendrobium laudereavorum M. Pignal , sp. nov.

( Figs 1A , 2 ; Table 1 )

Dendrobio finetiano Finet similis , sed floribus largioribus (12 mm vs 9 mm), lobis lateralibus labelli triangularibus (vs rotundatos), tepalis totis sursum (vs obliqua ), lobo mediano labelli paucituberculato (vs tuberculatum ), duobus lobis luteis (vs integros albosque), praecipue differt.

TYPUS. — Nouvelle-Calédonie. Province Sud, La Foa, Ouipoin, 21°41’10”S, 165°59’02”E, fl., jfr., 13.XII.2018, C. Laudereau & L. Laudereau 1234 (holo-, NOU [ NOU092603 ]!; iso-, G, K, P [ P02275932 ]!) .

PARATYPUS. — Nouvelle-Calédonie. Province Sud, La Foa, Ouipoin, 21°41’14.3”S, 165°59’10”E fl., 31.X.2021, C. Laudereau & L. Laudereau 1338 (para-, NOU [ NOU092709 ]!) .

ETYMOLOGY. — This new taxon is dedicated to my friends Christian and Pierre-Louis Laudereau. Christian has explored and studied the orchids of New Caledonia for twenty years with his wife Lydwine. His son Pierre-Louis accompanied him on many hikes. The photos presented in this paper are from Christian’s collection.

PHENOLOGY. — The taxon has been observed in flower and young fruit in December.

HABITAT AND DISTRIBUTION. — Dendrobium laudereavorum sp. nov. has been encountered in three places by Christian Laudereau (pers. comm.), two at Ouipoin in the commune of La Foa, and one about 10 km away near Koindé.

DESCRIPTION

Epiphyte with erect, closely spaced stems with a slightly bulging basal internode. Rhizome short, flexuous, branching sympodial. Stem flexuose, 200-250 × 1.5-5 mm, yellow and ribbed on dry material. Internodes, (10-)14-20(-23) mm. Leaves alternate with developed sheaths, slightly overlapping, same length as the internodes. Leaf blade narrowly ovate to elliptic, (30-)34-37(-43) × (5-)5.5-7(-7) mm, apex acute, rounded and asymmetrical. Inflorescence in subterminal racemes, (10-)23-38(-50) mm borne at the base of the sheaths to which they are axillary, making them appear opposite the next proximal leaf, sometimes on leafless stems, each bearing (2-)3(-6) flowers. Flowers resupinate. Triangular bracts c. 1 mm. Pedicel straight, 11 × 0.5 mm. Tepals dull on dorsal side and shiny on ventral side, yellowish green, revolute with edge revolute with age. Dorsal sepal obovate, 8 × 3.4 mm, with 3 longitudinal brown streaks and some transverse streaks (visible on ventral side). Lateral sepals, obovate to oblong, asymmetrical, 8.7 × 4 mm, with 3 longitudinal brown streaks extending to the tip, 2 lateral streaks slightly exceeding the lower half and with some transverse streaks (visible on the ventral side). Petals elliptic to obovate, 8 × 3.4 mm, somewhat asymmetrical with 4 brown streaks of unequal length. Mentum green, 2.6 × 1.5 mm, furrowed. Labellum, 10 × 7 mm, 3-lobed. Lateral lobes erect, triangular, 4.3 mm long and 2.5 mm high, white with pink tinge. Callus bright orange surmounted by 3 paler gibbosities. Median lobe panduriform, 8.5 × 9 mm, 3-lobed, dorsal side yellowish brown, ventral side with white hypochile, mesochile pink and epichile greenish. Lateral lobules triangular, white, 4 × 2.4 mm, median lobule with edges bent back 1.4 mm, with 2 central tuberculate ridges, reduced, epichile with 2 rounded rectangular lobes, 2.7 × 3.6 mm, divergent (forming an open angle of 150°). Column, 2.2 × 1.5-1.6 mm, c. 1 mm deep, greenish on the outside, enlarged at apex, furrowed ventrally, with dark orange macules at the apex near the anther, very pubescent at the furrow margins (white hairs up to 0.4 mm long). Lateral staminodes white, tinged with dark pink on the inside. Stigmatic cavity, 0.9 × 1 mm wide. Connective white, 0.8 mm wide and 0.6 mm high. Pollinia obovoid, dark yellow, 0.6 × 0.2 mm. Ovary, 2 × 1 mm, curved. Capsule fusiform to obovoid, green, 15 × 6 mm, pedicel c. 13 mm. Seeds ellipsoidal, c. 0.4 × 0.05 mm with green or orange embryo.

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/