Zygogynum archboldianum (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 : 41-42

1. Zygogynum archboldianum (A.C.Sm.) Vink — Fig. 1

Zygogynum archboldianum (A.C.Sm.) Vink (1985) 53. — Bubbia archboldiana A.C.Sm. (1942) 433. — Type: Brass 12712 (holo A; iso BO, BRI, L, LAE ).

Shrub 2–4 m high. Branchlets thick, black. Leaves scattered along branchlets; petiole 4 –11 mm long, flat above, rounded or keeled below, black; blade narrowly obovate, (6–)10–17 by 2.5–5 cm, coriaceous, (light) reddish brown below, apex obtuse (or somewhat acuminate) to rounded (or slightly emarginate), base narrowly acute, slightly recurved; midrib impressed above, triangular below; secondary nerves at 55–70° with midrib, towards margin joined by a distinct single or double row of arcs, (weakly) prominulous on either side. On lower leaf surface only stomata white, rather large, solitary, well-spaced, also over secondary nerves; no oil cells visible. Inflorescences red, with 5–11 partial inflorescences, these 4 – 8 cm long, with thick axes, 9–17(–38)-flowered; flowers inserted on axes 1st (or 2nd) order; empty bracts below inflorescence 1–4; pedicels 2–5 mm. Calyx 2–3- or irregularly lobed, 2–3 mm long, thin, smooth. Petals 4– 6, free, green, outer 4 elliptic to ovate, 5 –6 by 3–4 mm, apex broadly rounded, inner one(s) obovate or elliptic, 2.5–5 by 2–2.3 mm, apex rounded to obtuse. Stamens 13–17, 1–2 mm long; thecae apically touching; connective not prolonged; pollen in tetrads. Carpels 8–10, free, 1.8–2.5 by 1.0–1.5 by 0.8–1.2 mm; stigma over 0.5–0.8 of carpel apex and descending over 2/3 of adaxial carpel side; ovules 11–20. Young fruitlets hard, globose, up to 5 mm diam, stipe minute.

Distribution — Papua, Kab. Jayawijaya.

Ecology — (Gap in) tall mossy forest, 900–2100 m altitude. Flowering February, young fruits March.

Specimens examined. INDONESIA, Papua, Kab. Jayawijaya, 18 km SW of Bernhard Camp,Idenburg R., Brass 12712 (A,BO,BRI,L, LAE ), 2100 m alt.; 4 km SW of Bernhard Camp, Brass 13313 (A, BO, BRI, L), 900 m alt.

Notes — Brass 13313 was identified by Smith as Bubbia idenburgensis (here as synonym under Z. umbellatum ); that species has, however, on the lower leaf side also the unspecialised cells white.

Zygogynum archboldianum may look like Z. calothyrsum but differs by the stigma extending over the larger part of the adaxial carpel side.

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.).