Endiandra humboldtiana Munzinger & McPherson

Munzinger, Jérôme, McPHERSON, Gordon & Bruy, David, 2024, Novitates neocaledonicae XV: Two new species of Endiandra R. Br. (Lauraceae) from New Caledonia, Adansonia (3) 46 (3), pp. 19-28 : 21-24

Endiandra humboldtiana Munzinger & McPherson , sp. nov.

( Figs 1 ; 2 )

DIAGNOSIS. — Among New Caledonian species of Endiandra , the new species most closely resembles E. lecardii Guillaumin and E. neocaledonica Kosterm. because of its leaf size and shape and its leaf indument, each of them having hairs on the abaxial face of the blade that are short [not more than 1 mm long], appressed and eventually falling. However, in E. humboldtiana sp. nov., these hairs are denser, somewhat more persistent (typically remaining in at least protected areas of mature leaves vs quickly falling and rarely present on any but immature leaves); as well, these hairs are somewhat longer in E. humboldtiana sp. nov., [0.3-1 mm long vs 0.2 mm] and typically appear whitish at high magnification (vs reddish). Furthermore, the flowers of E. humboldtiana sp. nov., are 3 mm long [vs 2-2.5 mm in E. lecardii and E. neocaledonica ] and the new species appears to be endemic to the Mont Humboldt massif, from which E. lecardii and E. neocaledonica are not presently known.

TYPE MATERIAL. — New Caledonia • Province Sud, Nekando; alt. 1198 m; 21°51’48”S, 166°26’11”E; 20.XI.2019; fl.; J. Munzinger, G. McPherson, D. Bruy & C. Laudereau 8063; holo-, P[ P00864943 ]!, iso-, MPU [ MPU312580 ]!, NOU [ NOU091935 ]!).

PARATYPES. — New Caledonia • Province Sud, Mont Humboldt, c. 28 air-km N of Nouméa ; alt. 1550 m; [21°53’0”S, 166°25’0”E]; 20.IX.1980; fl.; G. McPherson 3119; para-, MO [ MO-3089854 ], NOU [ NOU016563 ], P [ P01963115 ] • Humboldt; alt. 1430 m; 21°52’32”S, 166°25’36”E; 30.VII.2009; fr.; J. Munzinger, F. Rigault, W. Nigote & C. Grignon 5719; para-, NOU [ NOU051038 ], P [ P02003042 ] • Thio, Nekando; alt. 1150-1300 m; 21°51’55.30”S, 166°26’7.37”E, 4.VI.2017, fr., D. Bruy & L. Barrabé 856; para-, NOU [ NOU106887 ] • Nekando; alt. 1198 m; 21°51’48”S, 166°26’11”E; 20.XI.2019; st.; J. Munzinger, G. McPherson, D. Bruy & C. Laudereau 8063bis; para-, MPU [ MPU312615 ], NOU [ NOU091936 ], P [ P00864959 ] (juvenile with leaves without epiphylls for molecular studies).

PHENOLOGY. — Flowers have been collected in September and November; fruits are known from June and July.

ETYMOLOGY. — The specific epithet refers to the type locality, Mt. Humboldt.

HABITAT. — The species grows in “Forêts denses humides d’altitude” on ultramafic rocks (peridotites), and more precisely in the orophilous facies with Lichens, Bryophytes and Hymenophyllaceae sensu Jaffré et al. (2012) , above 1150 m.

DISTRIBUTION AND ECOLOGY. — Endiandra humboldtiana sp. nov., is only known from the Humboldt Massif (Mont Humboldt & Nekando), in the southern ultramafic region of the main island ( Fig. 3 ).

CONSERVATION STATUS. — Endiandra humboldtiana sp. nov., is only known from one population, most of which is located in the “ Réserve naturelle du Mont Humboldt ”. The EOO calculated is 8 km ² and the AOO is 8 km ². The environment is well preserved and the population seems to be dynamic; no clear plausible threat seems to affect it. Consequently, E. humboldtiana sp. nov., has been assigned a conservation status of Least Concern (LC) by the New Caledonian Red List Authority on 23/02/2023 ( Endemia & RLA Flore NC 2022).

VERNACULAR NAME. — Unknown.

DESCRIPTION

Tree 6-10 m tall. Diameter up to c. 17 cm. Rauh's architectural model. Bark pale brown to grey, slash reddish.Terminal buds densely appressed-pubescent with greyish brown to white hairs, the young stems somewhat flattened in cross-section, 2.5-3 mm in width, eventually glabrescent and shallowly furrowed, lenticels slightly raised. Leaves alternate to subopposite; blades elliptic to obovate, 5.0-12.5 × 2.3-7 cm, base broadly acute to obtuse, usually symmetrical, apex obtuse or shortly and obtusely acuminate, texture subcoriaceous, adaxial and abaxial surfaces appressed-pubescent at first, the abaxial more densely and persistently so, with sheltered areas usually retaining some of their indument, the hairs 0.3-1.0 mm long, both surfaces at least partly glabrescent, the adaxial surface typically with raised oil cells at least along the midrib, these less obvious on the abaxial surface, lateral veins 4-6 on each side of the midrib, slightly raised (dried material) on both surfaces, as is the lesser venation; petioles 7-15 × 2-3.5 mm, flat adaxially, appressed-pubescent like the young leaf blades, glabrescent, petiole and primary vein yellow-orange in vivo.

Inflorescences axillary, 3-6.5 cm long, paniculate, the axes appressed-pubescent but glabrescent; peduncle 7-35 mm long, c. 1.5 mm wide; bracts narrowly triangular, 1-2 mm long, up to 0.75 mm wide, pubescent like the axes, pedicels 2.5-3.5 mm long. Flowers at anthesis greenish white, 3 mm long, c. 4 mm in diameter; floral tube densely pubescent within, with a distinct central depression in which the pistil sits; tepals ovate, 1.5-2.2 mm long, subequal, spreading at anthesis, rounded or widely acute apically, sparsely pubescent or glabrous abaxially, densely pubescent except along the margins adaxially; fertile stamens 3, c. 1 mm long, equalling the pistil, subsessile, filament and connective abaxially pubescent, anther locules latrorse-subintrorse, c. 0.6 mm long, glabrous, basal glands sessile, subspherical, c. 0.3 mm in diameter, glabrous; staminodes 3, c. 0.5 mm in length (i.e. c. half as long as the fertile stamens), subspherical to ovoid, glabrous or nearly so; pistil ovoid-elongate, c. 1 mm high, c. 0.5 mm in diameter at base, glabrous or with few scattered short hairs at the base, style attenuate, stigmata capitate, flattened. Fruit a single-seeded berry, black when ripe, elliptic-ovoid, 4.3-5.5 cm long and 2.4-2.8 cm in diameter, glabrous, seed colour in cross-section unknown.

NOTE

After we had detected the new species based on its morphology, some preliminary molecular data (unpublished) obtained by Chrissen Gemmill lent further support to its recognition. These new data, based on ITS sequences, which have demonstrated the greatest discrimination success for Lauraceae species ( Liu et al. 2022), indicate that E. humboldtiana sp. nov., (two accessions) is closely related to an undescribed taxon (one accession) only known from Roches de la Ouaième. The two taxa form a clade resolved as sister to a larger clade that includes E. lecardii (five accessions), E. neocaledonica (one accession), E. poueboensis Guillaumin (one accession), E. baillonii (Pancher & Sébert) Guillaumin (two accessions), and E. trichogyna sp. nov., (two accessions). Inside that large clade, E. poueboensis appears in sister position to a strongly supported clade (PP 0.95) that includes our six accessions of E. lecardii and E. neocaledonica . Thus, even though morphologically similar to them, E. humboldtiana sp. nov. is supported by molecular data as distinct from E. lecardii and E. neocaledonica .

Figures

FIG. 1. — Endiandra humboldtiana Munzinger & McPherson, sp. nov.: A, flowering branch; B, abaxial face of a mature leaf; C, zoom on abaxial face; D, inflorescences; E, flower; F, tepal of the exterior cycle, abaxial face; G, tepal of the exterior cycle, adaxial face; H, tepal of the interior cycle, abaxial face; I, dissected flower with tepals removed; J, isolated stamen; K, staminode; L, gynoecium; M, schema of a longitudinal section of the hypanthium and gynoecium; N, mature fruit. A-M, Munzinger et al. 8063; N, Munzinger et al. 5719. Drawings: Laurence Ramon. Scale bars: A-D, N, 1 cm; F-H, J-M, 500 µm; I, 1 mm.

FIG. 2. — Field pictures of Endiandra humboldtiana Munzinger & McPherson, sp. nov.: A, trunk and slash; B, adaxial face of a mature leaf; C, abaxial face of a mature leaf; D, vestiture on adaxial face of young leaves; E, inflorescences; F, flower and buds. A-F, Munzinger et al. 8063. Photographs: A, C, J. Munzinger; B, D-F, C. Laudereau.

FIG. 3. — Distribution of Endiandra humboldtiana Munzinger & McPherson, sp. nov. and Endiandra trichogyna Munzinger & McPherson, sp. nov. Abbreviation: T, indicates Type specimen. Colors: brown, ultramafic substrates; dark green, low and medium altitude humid dense forests; pale green, dense humid forests on limestone rocks (Jaffré et al. 2012).