Barringtonia serenae Jebb & Prance, 2011

Jebb, M. & Prance, G. T., 2011, Five new species of Barringtonia (Lecythidaceae) from Papua New Guinea, Blumea 56 (2), pp. 105-112 : 108-112

4. Barringtonia serenae Jebb & Prance , sp. nov. — Fig. 4

Species B. racemosa affinis,stylis curtibus ad medium filamentarum extensis, calycibus gemmarum inapertis,lobis calycibus post aperientis annulis cupuliformis remnatis, pedicellis articulatis differt, B. tagala affinis stylis curtibus, petiolis 2–7 cm (haud 1 cm) longis, petalis 38 mm longis, 22 mm latis (haud 22 × 15 mm) differt. — Typus: Jebb 905 (holo K; iso L), Papua New Guinea, Madang Province, River gorge 0.8 km W of Sein village, near Madang, by path to Og Cave, 5°18'S, 145°42.3'E, 90 m, 7 Apr. 1991.

Tree, leptocaul, 20 m tall, upright, bole 6 m, dbh 25 cm; bark smooth with large lenticels in ± regular rows, to 1 cm thick, 109 reddish, fibrous, soft; wood white; architecturally conforming to Champagnat’s Model; branches few, ± pendulous, upcurved at ends, ultimate twigs 8 –16 mm diam, its bark glabrous, smooth, to 3 mm thick; lenticels in ± straight rows, to 2 by 1 mm; leaf scars prominent, transverse-obovate, 1.3 by 1.7 cm; internodes 8 – 40 cm long. Leaves in whorls of 8 –11(–16), terminal; petiole 2 –7 by c. 0.8 –1.2 cm, rounded below, flattened above,

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glabrous, green, furnished with 2 abrupt ridges contiguous with the leaf blade, pulvinate in the lower 1/3 to 1/2 and there scabrous, grey-brown; leaf blades obovate; 13– 39(– 60) by 5.5–16.5(–24) cm, flat, coriaceous, dark dull green above, pale glossy green below; apex acuminate; base tapering, abruptly cuneate; midrib rounded below, narrowly ridged above; primary veins 10–14 pairs, prominent below ± above, arising obliquely, arched and united at the margin; margin asymmetrically crenulate, and minutely apiculate between crenulations, these becoming worn, ± entire towards base. Cataphylls leaf-like, below leaf whorls obovate, sessile; at stem apices broad-ovate, smallest 0.9 by 0.6 cm; apex acute; base truncate; margin serrate. Inflorescences lateral, from old leaf axils of branches, to 4 cm diam, rarely terminal on leafless shoots; racemes 1–5, 30– 35 by 0.5 cm, striate; pedicels to 3 mm long, 2 mm diam, thickened at their apices; bracts to 5 by 1 mm, minutely serrulate, caducous. Flowers 20 –28, opening sequentially 1–3 at a time; pedicels to 2.5 by 1 mm; buds spherical, apiculate, to 14 mm diam; splitting circumscissily at their widest point, glabrous, pale green, ± flushed with pink; calyx cupuliform, developing a red margin after corolla abscission; petals 4, obovate, puberulous, white, flushed with pink along the lower margins to 38 by 22 mm, fleshy at centre, membranous near margin, gently recurved along length; apex rounded; margins strongly recurved in open flower, giving the appearance of acute-triangular tapering petals 10 mm wide; stamens 200 –250, 30–40 by 0.5 mm (including the connate base), arranged in numerous whorls from the thick-walled (2.5 mm), 8 by 6 mm staminiferous tube, shortest towards centre of flower, innermost whorl anantherous, staminodes few, to 20 mm long, flattened, unbranched, tapering; anthers elliptic, 4-celled, 1.5 by 1 mm; style 20– 23 by 1 mm, tapering, white below, deep red in upper half; stigma flattened, capitate, to 2 mm across, ± 4-lobed, yellow; disc 8 mm across, with an annular scar from the staminiferous tube; within this scar a prominent, narrow, sharp-edged, cupuliform rim to 1 mm tall, and 5 mm diam, sloping inwards to base of style, yellow; ovary triangular, 6 by 9 mm broad, locules each with 2 ovules. Fruits unknown.

Distribution & Habitat — Madang Province. Rare? Only known from two collections. Growing on coral rock by river edge at 100 m.

Additional specimen examined. PAPUA NEW GUINEA, Madang Prov., 0.8 km NW of Sein Villlage, pathway to Og Cave , 5°18'S, 145°42.3'E, 90 m, Jebb 829 ( K, L) .

Note — The short style of this species, almost half the length of the stamens, and covered by the staminodes is a rare character in the genus. The failure of this tree to set fruit, even though it flowered successfully over the three years it was under observation (1988–1991), may be a result of its solitary existence, and an incompatibility mechanism, or it may be a consequence of the short style being incapable of receiving pollen. Some sterile collections from Morobe Province may pertain to this species or to B. clemensii . MJ names this species in honour of his delightful wife Serena who allowed him “the frivolous pursuit of hunting for Barringtonia , and who is also one of a kind.”

Figures

Fig. 4 Barringtonia serenae Jebb & Prance. a. Leaves and branch; b. inflorescence; c. bark; d. half flower (Jebb 905, K, L & 909, K).