Kermadecia brinoniae H.C. Hopkins & Pillon, 2019

Hopkins, Helen C. F. & Pillon, Yohan, 2019, Kermadecia brinoniae (Proteaceae: Macadamieae), a new species from New Caledonia previously confused with K. elliptica, Candollea 74 (1), pp. 85-92 : 86-90

Kermadecia brinoniae H.C. Hopkins & Pillon , spec. nova

( Fig. 1A–K ).

Holotypus: NEW CALEDONIA. Prov. Sud: Thy River Valley , c. 12 air-km NE of Nouméa [22°14'S 166°32'E], 200 m, 12.X.1979, McPherson 1945 ( P [ P02363286 ]! ; iso-: MO, NOU!, NSW).

Kermadecia brinoniae H.C. Hopkins & Pillon is most similar to K. elliptica Brongn. & Gris but differs by the more markedly raised venation on the lower leaf surface and by the base of the leaves, which is usually clearly cordate, rather than rounded, obtuse or weakly cordate.

Trees to 20 m tall, trunk to 30 cm diameter. Young twigs 4–7 mm diameter, with a dense covering of minute, ferruginous or greyish trichomes, these also present on the axillary buds and expanding adult leaves. Older twigs (proximal to the leaves) 5–8 mm diameter, glabrous, bearing some obscure lenticels and somewhat prominent heart-shaped to circular leaf scars. Bark brown, marked with grey and somewhat rough, or obscure, longitudinal furrows. Leaves in seedlings (based on MacKee 16340 & 37333): simple, petiolate; petioles 2–5 cm long, slender, hairy; blades variable in shape in a single seedling, elliptic, ovate, obovate or rhomboidal to partly lobed, sometimes asymmetric, 5.7 × 2.8 to 14 × 7 cm, papyraceous; base variable, cuneate to cordate, symmetric or not; apex acute; margins coarsely toothed, more strongly so towards the apex, teeth apiculate; abaxial surface coarsely hairy on the veins. Leaves in more advanced juvenile stages (including regrowth foliage; based on MacKee 16020 & 37332) imparipinnate, petiolate; petioles 9–27 cm long, 4–5 mm in diameter near the base, finely pubescent to glabrescent. Lateral leaflets in 5–6 opposite pairs, proximal ones with petiolules c. 1 cm long, distal ones ± sessile; blades ovate, oblong-elliptic or oblong, 8.5– 17 × 4– 9 cm, base cordate or rounded, asymmetric and often oblique, apex acute-acuminate to somewhat truncate, margins entire or with a few coarse apiculate teeth towards the tip, papyraceous to coriaceous. Terminal leaflet similar in length to the most distal laterals, obovate to ± round, sometimes asymmetric with a large lobe prefiguring a lateral leaflet, in symmetric leaflets base cuneate to subcordate, apex acute-acuminate, margins entire or with a few coarse apiculate teeth near the tip. Leaves in adult plants simple, petiolate; petioles 2–8.5 cm long, pulvinate at the base, terete above, with faint longitudinal striations and an indumentum of minute, curled, ferruginous (plus sometimes a few white) trichomes, glabrescent; blades oblong-elliptic, ovate, broadly ovate or elliptical-obovate, (6.2–)9.5–18.5 × (3.8–) 7–10.5 cm, cordate at the base, rounded or broadly obtuse towards the apex, apex often retuse or splitting in older leaves, margins ± entire to somewhat irregular or sinuate (rarely coarsely toothed distally); secondary veins c. 5–7 on either side of midrib, angle to midrib 40–50° in mid-part of leaf, venation brochidodromous; abaxial surface said to be light shiny green when fresh but commonly drying mid-brown, with scattered minute ferruginous or whitish trichomes on the midrib, secondary and tertiary veins (hairs c. 0.1 mm), intervenium and higher order venation almost glabrous, with minute “glands” (hair bases) associated with higher order venation, midrib markedly prominent for its entire length and usually sharply so, secondary, tertiary and at least some quaternary veins also sharply prominent, this readily visible in dried material; adaxial surface said to be dark shiny green when fresh, usually drying yellowish green except for youngest leaves which dry dark brown, glabrous except for some minute trichomes at the base of the midrib, midrib, secondary and tertiary venation flat or slightly indented, or tertiary and quaternary venation sometimes minutely raised, areoles visible or not in dried material. Inflorescences: axes either proximal to the leaves, arising singly on woody stems to 2 cm diameter or sometimes axillary (supra-axillary?), each axis 11–25 cm long × 3–5 mm diameter just above the basal attachment (which is broader), somewhat ridged longitudinally, unbranched, erect or somewhat spreading, the flowers opening simultaneously in any inflorescence (at least in herbarium material); pairs of free pedicels or their scars ± evenly spaced along the entire length of the axis, almost to its base; pedicels 13–16 mm long (– 22 mm soon after flowering) × 1 mm diameter, terete, arising in collateral pairs, each pedicel subtended by a small, thick bract, or bracts fused (and then sometimes bract bilobed at the tip); pedicels oblique at their distal end, up to 4 mm longer on one side than the other; rachis, pedicels and bracts covered by a dense indumentum of minute, curled, ferruginous trichomes. Flowers: buds on the point of opening to 16 mm long, unequal and expanded at the base, then forming a narrow tube above (9–12 × 1.5 mm), and distal part globose (4 × 4 mm); apical lobes of tepals thick, each bearing a single anther with 2 thecae on the inner surface; outer surface of tepals covered by a dense indumentum of minute, ferruginous, curled trichomes, inner surface glabrous except at the margins and drying almost black except for the lobes which have a paler, granular surface; post anthesis, tepals splitting apart to the base of the flower, ± spoon-shaped, all reflexed and/or somewhat curled; anthers 2.5 × 1 mm, thecae dehiscing longitudinally, connective minutely prolonged at the apex; disc semi-circular or crescent-shaped around the base of the ovary, well developed on the side of the flower where the pedicel is shorter, lacking on the side where the pedicel is longer, glabrous, drying almost black; ovary cylindrical-conical, c. 5 × 1.5 mm, gradually tapering into the style, outer surface with a dense indumentum of ferruginous trichomes, less curled than those on the outer surface of the tepals; style c. 13 mm long, slightly furrowed longitudinally, hairy towards the base with a few scattered hairs distally, drying almost black, straight except for the distal 2 mm which are often narrower and slightly bent and sometimes flattened on the lower surface in flowers post anthesis, forming a densely hairy pollen presenter at anthesis, the hairs readily breaking off. Fruits when fresh: epicarp shiny black when ripe (fide MacKee 16339), outer mesocarp quite thick and fibrous or succulent, inner mesocarp very hard; dried fruits (MacKee 16339) appearing hard, woody, with the surface ± smooth to slightly corrugated, sometimes developing a few irregular fissures associated with the corrugations (artefact of drying), 4.5–4.8 × 2 × 2.5 cm, elliptic-obovate and inequilateral in lateral view, evenly curved along the ventral line, slightly angled distally along the dorsal line; base cuneate with the scar almost centrally placed, 4 mm in diameter; blunt towards the apex, apex with a small mucro (remnant of the style-base) located towards the ventral margin; in cross-section, inner mesocarp ± trullate, angled especially at the dorsal line.

Etymology. – The epithet of this new species honours Helen Brinon, who had a keen interest in the New Caledonian flora and who collected more than 800 numbers between 1976 and 1987, mostly from the Thy (or Thi) Valley, where K. brinoniae has been found. Helen Brinon was British but a long-term resident in New Caledonia, where she was the wife of Marcel Brinon, who worked for the Service des Eaux et Forêts de la Nouvelle-Calédonie. Before coming to New Caledonia, she had done ethnobotanical work in the north of Australia (T. Jaffré pers. comm.; G. McPherson, pers. comm.; MORAT, 2010).

Distribution, habitat and phenology. – This species is a rainforest tree known from only a few localities in the south of Grande Terre, New Caledonia ( Fig. 2 ). The substrate is either ultramafic or unclear, in areas where a mosaic of rocks is known to occur.

Buds have been collected from October to December, flowers in October and November and mature fruit in January.

Conservation status. – The new species is known from 4 or 5 populations, only one of which occurs within a protected area (Réserve naturelle de la Vallée de la Thy). Its habitat, rainforest, is fragmented and declining because of fire. Dispersal of this large-fruited, large-seeded taxon may be problematic because of hunting pressure on its putative dispersers (flying foxes and New Caledonian Imperial Pigeons). Kermadecia brinoniae will be evaluated by the New Caledonia Red List Authority but would probably qualify as “Endangered” [EN B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)] under the IUCN Red List Categories and Criteria ( IUCN 2012, 2017), based on its AOO of 30 km ² and EOO of 20 km ² and the fact that it is known from fewer than 10 locations.

Notes. – In K. brinoniae , the secondary, tertiary and at least some quaternary veins are sharply raised on the lower surface of the leaf blades in adult leaves, whereas on the lower leaf surface of K. elliptica , the secondary veins are less strongly raised, and the tertiary and higher order venation are flat or almost so. In K. brinoniae , the areoles are typically less visible in dried material than they are in K. elliptica and the base of the blade is clearly cordate, whereas in K. elliptica it is rounded, obtuse or scarcely cordate and often slightly unequal. The two species also occur on different substrates, K. brinoniae on ultramafic ones or mosaics including ultramafic, and K. elliptica on non-ultramafic substrates.

The following details of floral colour have been noted on specimen labels: MacKee 29240, tepals brown on outside, yellow inside; ovary brown, style greenish yellow; MacKee 37331, tepals in full bloom pale yellow with reddish pubescence on the outside; McPherson 1945, perianth brownish yellow outside, cream-coloured within; style brown at base, green distally, apex cream-coloured, often with a central purple dot.

Measurements with a handheld X-Ray Fluorescence (XRF) spectrometer ( GEI et al., 2018) indicated that K. brinoniae can accumulate a moderate amount of manganese in its leaves: 665 µg g- ¹ in MacKee 16019, 769 in Sarlin 75, 906 in MacKee 5284, 1233 in MacKee 16399, and 2158 in MacKee 29240. The accumulation of manganese is a typical characteristic of New Caledonian Proteaceae growing on ultramafic substrates ( JAFFRÉ, 1979). According to JAFFRÉ (1980), 21 % of the species growing on ultramafic substrates in New Caledonia have a leaf Mn concentration exceeding 1000 µg g-¹, thus, the Mn content of K. brinoniae is not unusual considering its ecology.

Paratypi. – NEW CALEDONIA. Prov. Sud: Thy, upper Home Track , 250 m, 12.X.1980, buds & old fl., Brinon 873 ( NOU) ; Robinson, forêt “ Lavoix ”, 14.XI.2011, buds, Chambrey [leg. S. Grenda et al.] 130 ( NOU) ; Forêt “ Demazures ”, 14.XI.2011, old fl., Chambrey [leg. S. Grenda et al.] 131 ( NOU [2 sheets]) ; Forêt de la Thy , 20.XII.1983, seedling, Lauri 116 ( NOU) ; Vallee de Thy, slope towards Mt Koghi , 300–400 m, 22.IX.1956, buds, MacKee 5284 ( BM, K, P) ; Pente au N de la Conception, 200–400 m, 6.XII.1966, buds & old fl., MacKee 16019 ( K, NOU, P [2 sheets]) ; ibid. loco, rejet du tronc (see MacKee 16019), MacKee 16020 ( K, NOU, P [2 sheets]) ; Pente au N de la Conception, 200 m, 23.I.1967, fr. & st., MacKee 16339 ( K [1 sheet, carpo.], NOU, P [2 sheets, carpo.]) ; ibid. loco, seedling, MacKee 16340 ( P) ; Route de Yate, Les Dalmates , 150 m, 8.IX.1974, fl., MacKee 29240 ( NOU, P) ; Forêt de Thy , 100 m, 21.IX.1979, fl., MacKee 37331 ( K, NOU, P) ; ibid. loco, juv.lvs, MacKee 37332 ( NOU, P [2 sheets]) ; ibid. loco, seedling, MacKee 37333 ( NOU, P) ; Forêt de Thy , s.d., buds & fl., Sarlin 75 ( P [2 sheets]).

Figures

Fig. 1. – Kermadecia brinoniae H.C. Hopkins & Pillon (A–K) and K. elliptica Brongn. & Gris (L–M). A. Vegetative shoot; B. Detail of leaf, abaxial surface, all veins raised except the finest branches, these shown as dotted lines; C. Inflorescence (total length 21.5 cm), showing flowers in pairs; D. Pair of flowers from C, each flower on a free pedicel (apex of axis to the left); E–F. Lateral and ventral view of opened flower with only one tepal remaining, to show the disc; G. Inner face of distal portion of tepal, showing a stamen; H–I. Apical and lateral views of mature fruit; J–K. L.S. and T.S. of mature fruit (black shading = very dense endocarp); L. Leaf, adaxial surface; M. Detail of L, abaxial surface, midrib and secondary veins raised, note numerous small areoles. [A–G: McPherson 1945, P; H–K: MacKee 16339, P; L–M: Vieillard 1106, K] [Drawing: Andrew Brown]

Fig. 2. – Map showing the distribution of Kermadecia brinoniae H.C. Hopkins & Pillon (open squares) and K. elliptica Brongn. & Gris (solid circles, omitting collections by Vieillard as the localities are imprecise). Areas with ultramafic substrates are shown in grey.