Syzygium radiciflorum 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 : 76

32. Syzygium radiciflorum Craven & Damas , sp. nov. — Fig. 2 : 3.3; Map 8

From Syzygium branderhorstii Lauterb. it differs in the leaf lamina lacking a secondary intramarginal vein (secondary intramarginal vein present in S. branderhorstii ); a pair of much-reduced leaves within the inflorescence (inflorescence leafless in S.branderhorstii ); and 6‒7 ovules per locule (13‒18 in S. branderhorstii ). — Type: Hoogland 4198 (holo CANB!; iso LAE !), Papua New Guinea,Northern (Oro) Province,Tufi Subprovince,c. 2 km NW of Nauk- wate village, in tall secondary forest on wet soil, alt. c. 50 m, 25 June 1954.

Tree to 9 m tall, to 4 cm dbh; bark grey-green, flaky or papery. Vegetative branchlet terete or compressed, rounded, 1.5‒ 2.5 mm diam; bark dull, smooth or cracked and furfuraceous, not glandular-verrucose, flaking in relatively large pieces. Leaf lamina elliptic, 16‒22.5 by 7‒10.5 cm wide, 1.9‒2.6 times as long as wide; base not cordate; apex obtuse, or sometimes short acuminate; acumen flat; margin flat or slightly revolute; primary and secondary venation generally similar with all or nearly all secondaries joining the intramarginal vein; primary veins 20‒26 on each side of the midrib, in median part of lamina at a divergence angle of 60‒70° and 4‒10 mm apart; intra- marginal vein present, weakly arched, 1–3 mm from margin, secondary intramarginal vein absent. Petiole 10‒20 mm long. Reproductive seasonal growth unit with a reproductive zone only. Inflorescence leafy (a pair of reduced, narrowly elliptic leaves up to 75 by 15 mm subtends the first pair of branchlets in the inflorescence), on branchlets below the leaves, cauline or radicine, many-flowered, paniculate, up to at least 21 by 26 cm, major axis c. 4 mm thick at the midpoint, bark furfura- ceous; bracts persistent; bracteoles subtending each flower or subtending lateral flowers of a triad but with the terminal flower ebracteolate, persistent. Flower buds with the apex rounded to obtuse. Flowers pinkish white. Hypanthium dull, visibly gland-dotted, minutely (but distinctly) wrinkled, ribbed, stipitate; goblet-shaped or goblet-shaped-without-the-stipe, 4‒5 by c. 3.5 mm, stipe up to 0.5 mm long. Calyx lobes 4, transversely semi-elliptic or very depressedly triangular, 0.5‒0.6 mm long. Petals 4, calyptrate (coherent and falling as a cap). Staminal disc ascending ( Fig. 2 : 3.3). Stamens c. 50, 3.5‒8 mm long. Style c. 7 mm long. Placentation axile-median; placenta a more or less narrowly elliptic to oblong cushion. Ovules 6 or 7 per locule, ascending, apparently arranged irregularly. Fruit not seen.

Distribution — Papua New Guinea.

Habitat & Ecology — Tall secondary forest on wet soil, light forest by stream. Altitude 50‒300 m.

Notes — 1. Given the often variable positioning of inflores- cences in Syzygium (within an individual plant the inflores- cences may be inserted among the leaves, on the branchlets below the leaves, on the major branches and on the trunk), the development of inflorescences on exposed roots should not be unexpected. In the material of Hoogland 4198 deposited in CANB, inflorescences are inserted at the base of the trunk (fide Hoogland in herb.) and on the roots, the latter presum- ably having become exposed by the removal of leaf litter, etc., and stimulated by increased light reception so as to produce inflorescences. The inflorescences in Pullen 7718 are inserted on branchlets below the leaves.

2. The species is known from two collections only.

Figures

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