Zygogynum umbellatum (Ridl.) Vink

Vink, W., 2016, The Winteraceae of the Old World. VIII. Some Zygogynum species from New Guinea, Blumea 61 (1), pp. 41-50 : 49-50

16. Zygogynum umbellatum (Ridl.) Vink — Fig. 1

Zygogynum umbellatum (Ridl.) Vink (1985) 54. — Drimys umbellata Ridl. (1916) 11. — Bubbia umbellata (Ridl.) Dandy (1934) 41;A.C.Sm.(1943) 150. — Type: Boden Kloss s.n. (K).

Bubbia glauca A.C.Sm. (1942) 433, (1943) 150. — Zygogynum glaucum (A.C.Sm.) Vink (1985) 54. — Type: Brass 7191 (holo A n.v.; iso BO, BRI, L, LAE ).

Bubbia idenburgensis A.C.Sm.(1942) 432,(1943) 150. — Type: Brass 13028 (holo A n.v.; iso BO, BRI, L).

Tree(let) 2–10 m high. Branchlets rather slender,brown. Leaves: petiole 8 – 20 mm long, broadly grooved to flat above, rounded below, dark brown; blade obovate to oblanceolate, 7–23 by 3–8 cm, chartaceous to thin-coriaceous, in sicco light grey (rarely brownish grey) below; apex acute and 0–1.8 cm (broadly) acuminate, base cuneate; midrib slender to broad, impressed above, (strongly) prominent below; secondary nerves at 55–75° with midrib, towards margin joined by a – sometimes double – row of arcs, faint to distinct on either side. On lower leaf surface stomata and unspecialised cells white, also over secondary nerves, sometimes tiny islands of unspecialised cells bare; oil cells (not apparent to) abundant, often black. Inflorescences with 3–9 partial inflorescences, these (1–) 3–11 cm long, with slender but under fruit firm axes, 3–15(–61)-flowered, flowers inserted on axes 1st or 2nd (to 3rd) order; empty bracts below inflorescence 0–6; pedicels 2–9 mm long, slender to rather firm. Calyx 2- or irregularly lobed, often reflexed, 0.4–1.4 mm long, smooth. Petals 4, free, elliptic to orbicular or (ovate-) oblong, (purple-)green, 2–4 by 1.5–4 mm, apex (broadly) rounded. Stamens 6–19, 1–1.5 mm long; thecae apically touching to distinctly separated; connective not prolonged, pollen in tetrads. Carpels 1–6, free, 1.5–2 by 1–1.5 by 0.8–1.5 mm; stigma 0.6–0.8 times as long as carpel apex, adaxially descending 1/4–1/3 carpel height; ovules 8–22. Fruitlets a hard berry, globose (to obovoid), red, in sicco not showing seeds, up to 12 mm diam, base obtuse to rounded with an up to 1.5 mm long stipe; stigma 3–6 mm long, apico-ventral; fruitwall with dense brachysclereids; pulpa from only as ridges on locule wall to completely separating seeds. Seeds 5–13, obovoid, 3–5.3 by 1.8–3.5 by 1.5–3.2 mm; testa rather thin, brittle, dull to shining black, (sub)smooth.

Distribution — Rare throughout New Guinea.

Ecology — In undergrowth of primary or mixed secondary forest at 100–1200 m altitude. Flowering November–February, fruiting March–July.

Vernacular name — Kakĕta (Maybrat lang.).

Specimens examined. INDONESIA, Papua, Kab. Teluk Bintuni, Bomberai Peninsula, Sjuga-Wagura area,Armina, V.W. Moll BW 13003 (A, BRI, CANB, K, L), below 400 m alt.; Kab. Sorong Selatan, Vogelkop Peninsula, Ayawasi, W.Avé 4456 (L), 450 m alt.;Kab.Mimika,Mt Carstensz,camp VIb, Boden Kloss s.n. (K), 1200 m alt.; Kab. Jayawijaya, Bernhard Camp, Idenburg R., Brass 13028 (A n.v., BO, BRI, L). – PAPUA NEW GUINEA, Western Prov., nr junction Black R. with Palmer R., Brass 7191 (BO, BRI, L, LAE ), 100 m alt.; Gulf Prov., Lakekamu, Avi Avi R., Takeuchi & Kulang 11547 (L), 175 m alt., 11568 (L), 335 m alt.; Morobe Prov.,Aseki, Schodde & Craven 5082 (A, L), 1200 m alt.

Notes — This species differs from Z. polyneurum only by the brachysclereids in the fruit wall, causing hard berries, but I prefer to uphold this fruit character as one of the few distin- guishing characters in the papuasian species complex.

Zygogynum umbellatum occurs in lowland and lower montane habitats, rather unusual for New Guinea Winteraceae .

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.).