Zygogynum megacarpum (A.C.Sm.) Vink

Vink, W., 2016, The Winteraceae of the Old World. VIII. Some Zygogynum species from New Guinea, Blumea 61 (1), pp. 41-50 : 47

9. Zygogynum megacarpum (A.C.Sm.) Vink — Fig. 1

Zygogynum megacarpum (A.C.Sm.) Vink (1985) 53. — Bubbia megacarpa A.C.Sm. (1942) 434. — Type: Brass 10249 (holo A; iso BO, BRI, L, LAE ).

Treelet 3–8 m high, dbh c. 10 cm. Bark reddish brown, rugose. Branchlets rather slender to stout, light to medium brown. Leaves scattered along branchlets; petiole 6 –12 mm long, with raised margins above, rounded below, dark brown; blade narrowly obovate to oblanceolate (or narrowly elliptic), 10–18 by 3–5.5 cm, (thick) chartaceous, in sicco brown below; apex broadly rounded to obtuse or with an up to 0.5 cm long rounded acumen, base often with recurved margins, (narrowly) acute; midrib impressed above, strongly prominent below; secondary nerves at 55–70° with midrib, arcingly joined at some distance from margin, (rather) distinct above, weak to distinct below. On lower leaf surface probably only stomata white, solitary and in small strings and clusters, also over secondary nerves; oil cells many. Inflorescences with 3–7 partial inflorescences, these 4–8 cm long, with firm axes, rather many-flowered, flowers inserted on axes (1st or) 2nd to 3rd order; empty bracts below inflorescence 0–3; pedicels 3–13 mm, rather slender. Calyx 2–3- or irregularly lobed, 0.8–1.5 mm long, thin, smooth. Petals 4 (rarely 5), free, elliptic to obovate, white, 5–7 by 4–5 mm, apex broadly rounded. Stamens 15–21, 1.3–1.6 mm long, thecae at wide angle, apically slightly separate to touching; connective not prolonged; pollen in tetrads. Carpel solitary, squarish but somewhat narrowed at base, 2–3 by 2.5–3.5 by 1.5–2.5 mm; stigma over entire carpel apex and descending at the ventral side almost to the base; ovules c. 50–68. Fruit a soft berry, red, globose to transverse-ellipsoid, 3–3.5 by 3–4 cm in sicco; pulpa in thin plates completely enveloping seeds. Seeds many, usually flattened, obovoid and tapering towards base to comma-shaped, 4–6 by 2.5–4 mm; testa thin, grey, finely low-pusticular.

Distribution — Papua: Kab. Jayawijaya.

Ecology — Near streams in montane ( Casuarina­Podocarpus­Dacrydium) forest at 2100–2800 m altitude. Flowering May, October; fruiting October.

Specimens examined. INDONESIA, Papua, Kab. Jayawijaya, 9 km NE of Lake Habbema, Brass 10249 (A, BO, BRI, L, LAE ), 2800 m alt.; Km 48 on Wamena–Pass Valley Rd, Burley & Ismail 4618 (L), 2100 m alt.

Notes — This species is characterized by its solitary carpel, with the stigma over the entire apex continuing almost to the base of the ventral side, developing into a relatively large fruit. Due to the collecting method, the white layer on the lower leaf surface disappeared almost entirely.

Figures

Fig. 1 Carpels, all with ventral side to the left, and at the same magnification. – a. Zygogynum archboldianum; b. Z. bosavicum; c. Z. clemensiae; d. Z. cruminatum; e. Z. cyclopensis; f. Z. ledermannii; g, g'. Z. longifolium; j. Z. megacarpum; h. Z. montanum; i. Z. oligocarpum; k, k'. Z. polyneurum; l. Z. schramii; m. Z. sororium; n. Z. staufferianum; o. Z. umbellatum (a. Brass 12712; b. LAE 58822; c. Clemens 4596; d. LAE 69143; e. Royen & Sleumer 6396; f. Takeuchi 6212; g. Vink BW 8413; g'. Robbins 2004; j. Burley & Ismail 4618; h. LAE 61131; i. Schlechter 16470; k, k'. Jacobs 9489; l. Vink BW 8458; m. Ledermann 11898; n. Balgooy 968; o. Boden Kloss s.n.).