Zygogynum bosavicum Vink, 2016

Vink, W., 2016, The Winteraceae of the Old World. VIII. Some Zygogynum species from New Guinea, Blumea 61 (1), pp. 41-50 : 42-43

2. Zygogynum bosavicum Vink , sp. nov. — Fig. 1

Zygogynum bosavicum Vink. — Type: Damas LAE 58822 (holo L).

Shrub or understory tree, up to 8 m high. Branchlets rather slender, light to dark brown. Leaves scattered along branchlets, sometimes tufted terminally below infructescence; petiole 4–14 mm long, flat above, rounded below, dark brown; blade obovate, (4–)7–15 by (2–) 2.5–6 cm, coriaceous, light greyish brown below, apex obtuse and up to 5 mm (broad-)acuminate, base narrowly acute, recurved; midrib impressed above, prominent below; secondary nerves at (60–)70–80(–90)° with midrib, towards margin joined by a distinct – usually double – row of arcs, (slightly) impressed above, prominulous to prominent below. On lower leaf surface stomata large, white, well-spaced to dense, solitary to clustered, not over secondary nerves; usually no oil cells visible. Inflorescences with (3–)5–8 partial inflorescences, these (2.5–) 5–11 cm long, with rather thin axes, c. 6–18-flowered, flowers inserted on axes (1st or) 2nd to 3rd (or 4th) order; pedicels 2–10 mm. Only fruits seen. Calyx 0.4–0.7 mm long. Carpels 3–5; in old carpels stigma over whole length of apex and descending adaxially half way down. Fruitlets a hard berry, globose to obovoid, up to 8 mm high; terete stipe (0–0.5 or) 1 mm long, stigma apical-ventral, 2–5 mm long, outer layer of rather thin fruitwall with small clusters of brachysclereids, pulpa not between seeds. Seeds several, narrowly obovoid to ellipsoid, rarely slightly curved, 3.5–4(–4.5) by 1.5–2 by 1.5(–2) mm; testa dark grey, smooth.

Distribution — PNG, Western and Southern Highlands.

Ecology — Montane (mixed, laurofagaceous, Nothofagus­ Syzygium, Araucaria­Nothofagus) forests, 700–1900 m altitude. Fruiting July–September.

Vernacular names — Karli ( Enga lang.), Tifep (Mendi lang.).

Galls — Galls are present in one specimen ( LAE 57353), and form a train of globose, 2–3 mm large thickenings next to or close to the midrib. About 1/3 of a gall is on the upper leaf side and slightly darker than the dry leaf; the more bulgy lower side is dark grey-brown, but the epidermis shows the normal distribution of white stomata; here are also the small, ellipsoid exit openings, with a distinctly demarcated narrow border of small cells.

Specimens examined. PAPUA NEW GUINEA, W. Highlands Prov., Kiunga Dist., Ok Kam, Moiyokabip (NE of Tabubil), Frodin UPNG 4465 (L), 1350 m alt.; Pokaris nr Kompiam, Flenley ANU 2883 (K, L), 1860 m alt.; S. Highlands Prov., Mt Bosavi, Jacobs 8745 (L), 1250–1350 m alt., Gideon LAE 57353 (L), 1500 m alt., Damas LAE 58822 (L), 800–900 m alt., Katik LAE 77988 (L), 700 m alt.; Lake Kutubu, Tabage, Coon & Kairo 475 (L); Mendi valley, above Kiburu, Schodde 1389 (A, CANB, K, L, LAE ).

Note — Although only fruits are known, this is an easily rec- ognizable species, characterized by the strong, dark coloured secondary nervation on the lower leaf side and the more or less distinctly recurved base of the coarse leaves. However, in ANU 2883 and Schodde 1389 the secondary nerves and their extra arcs are less strongly developed.

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.).