Syzygium royenii Craven & Damas, 2021

Craven, L. A., Damas, K. Q. & Cowley, K. J., 2021, Studies in Papuasian Syzygium (Myrtaceae): 2. The furfuraceous species of subg. Syzygium, Blumea 66 (1), pp. 57-81 : 77

34. Syzygium royenii Craven & Damas , sp. nov. — Fig. 2 : 1.2; Map 9

From Syzygium furfuraceum Merr. & L.M.Perry it differs in having smaller leaves with a lamina 2.5‒5.3 by 1.4‒1.7 cm, a cuneate base and 10‒16 primary veins on each side of the midrib (lamina 8.5‒19.5 by 3‒19.3 cm,the base obtuse and the veins 30‒37 in S. furfuraceum ); and the hypanthium dull or dull-glossy, not furfuraceous, minutely wrinkled, or 2-costate (dull, furfuraceous, smooth or striate in S. furfuraceum ). — Type: NGF (Croft & Lelean) 34941 (holo CANB!; iso LAE !,A, BISH, BRI, E, K, L, M, NSW, PNH, QRS, US, all n.v.), Papua New Guinea, Central Province, Port Moresby Subprovince, E slope to Lake Myola No. 1, submontane rainforest-moss forest, alt. c. 2100 m, 28 Sept. 1973.

Etymology. The specific epithet honours Pieter van Royen (1923‒ 2002), a significant collector of, and author on, the flora of New Guinea.

Tree to 50 m tall, to 120 cm dbh; outer bark orange, inner straw, papery. Vegetative branchlet terete in mature branchlets, quad- rangular in immature branchlets, rounded or angled, 2‒4 mm diam; bark dull, bark more or less smooth, not glandular-verrucose, flaking in relatively large pieces. Leaf lamina narrowly elliptic or sometimes obovate, 2.5‒5.3 by 1.4‒1.7 cm, 1.7‒2.3 times as long as wide; base cuneate; apex acute, flat; margin flat; coriaceous; primary and secondary venation distinctly different with secondaries relatively little developed and not or rarely joining the intramarginal vein; primary veins 10‒16 on each side of the midrib, in median part of lamina at a divergence angle of 70‒80° and 1‒2 mm apart; intramarginal vein more or less parallel to the margin to weakly arched, 0.05‒1 mm from margin, secondary intramarginal vein absent. Petiole 5‒7 mm long. Reproductive seasonal growth unit with a reproductive zone only. Inflorescence leafless, on branches or cauline, paniculate, up to 17 by 13 cm, major axis 3‒4 mm thick at the midpoint, bark furfuraceous; bracts caducous; bracteoles subtending each flower, caducous. Flower buds with the apex rounded to obtuse. Hypanthium dull or dull-glossy, visibly gland-dotted or not, minutely but distinctly wrinkled or angled laterally (i.e., 2-costate); stipitate; stipitate-cup-shaped, 3‒4.5 by 2‒3.5 mm, stipe 0.5‒1 mm long. Calyx lobes 4, relatively distinct or discernible as points on a rim of tissue, very depressedly triangular when well developed, 0.2‒0.4 mm long including the rim. Petals?4, calyptrate (coherent and falling as a cap). Staminal disc flat ( Fig. 2 : 1.2). Stamens c. 70. Placentation axile-basal; placenta a small cushion. Ovules c. 12 per locule, ascending, arranged irregularly. Open flowers and fruit not seen.

Distribution — Papua New Guinea.

Habitat & Ecology — Submontane rainforest-moss forest, submontane rainforest, in Nothofagus -Astronia forest. Altitude 1520‒2650 m.

Note — The only reproductive material seen was in the late bud stage. The petal number is unclear and it may be that some of the petals are connate.

Map 9 Distribution of Syzygium royenii Craven & Damas (●), S. sambogense T.G.Hartley & L.M.Perry (▲), S. squamatum Merr. & L.M.Perry (★), S. takeuchii Craven & Damas (◆), S. whitmorei Craven & Damas (Å).

Figures

Fig. 2 Staminal disc types in Syzygium species. Series 1: Flat; series 2: descending; series 3: ascending; series 4: raised.