Zygogynum clemensiae (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 : 43

4. Zygogynum clemensiae (A.C.Sm.) Vink — Fig. 1

Zygogynum clemensiae (A.C.Sm.) Vink (1985) 53. — Bubbia clemensiae A.C.Sm. (1942) 431. — Type: Clemens 5157 (holo A n.v.).

Shrub or treelet. Branchlets (rather) stout, brown. Leaves scattered along branchlets; petiole 5 – 20 mm long, flat to broadly grooved above, rounded below, dark brown; blade elliptic to obovate, 11–29 by 4–10 cm, subcoriaceous, light yellowish, pale green, greenish brown, or glaucescent below; apex obtuse or rounded to slightly emarginate, base acute or slightly attenuate; midrib slightly grooved to slightly raised above, prominent below; secondary nerves at 55–75(–90)° with midrib, arcingly joined at some distance from midrib, prominulous on either side. On lower leaf surface stomata white, solitary or also in well-spaced clusters, also (but sometimes scarcely) over secondary nerves; oil cells many or indistinct. Inflorescences with 3–6 partial inflorescences, these 2–7 cm long, with stout axes, 1–3-flowered; empty bracts below inflorescence 3–7; pedicels 5–30 mm long, in solitary flowers 10–70 mm long, stout. Calyx 2–3- or irregularly lobed, 2–3 mm long, rather thin, smooth. Petals 8, in 2 series or all in one series, 1/4–3/4 connate but petals of inner series free, dark maroon, elliptic-oblong, thick, 11–17 by 5–12 mm, apex rounded. Stamens 70–(fide Smith)125, 2–3.5 mm long, filaments inflated, white; thecae apically separate or touching; connective not prolonged; pollen in tetrads. Carpels 5–11, free, in bud free or coherent, c. 3 by 3 mm, with relatively long apex; stigma as long as carpel apex or slightly protruding abaxially; ovules 15–20 seemingly in more than one row. Fruitlets a hard berry, obovoid to globular, green, up to 15 mm diam; base obconical to rounded, stigma apical, 5 – 8 mm long, distinct; outer layer of fruitwall with clusters of brachysclereids; pulpa not between seeds. Seeds 5–∞, obovoid, up to 5 by 3 by 3 mm; testa rather thick, dull grey-brown and locally black, or black, on free surface with tendency to form ribs .

Distribution — PNG, Madang to Morobe Provinces.

Ecology — Hill forest or stunted cloud forest on ultrabasics, at 1350–1860 m altitude. Flowerbuds January,August; flowering December; fruiting March, July.

Specimens examined. PAPUA NEW GUINEA, Madang Prov., Saidor Subprov., Wumundi, Sayers NGF 19772 (A, L), 1500 m alt.; Eastern Highlands Prov., Numura, 6 miles from Kainantu towards Goroka, Stauffer & Sayers 5611 (K, L, US), 1860 m alt.; Morobe Prov., Ogeramnang, Clemens 4596 (A, B), 1740 m alt., Yunzaing, Clemens 3629 (A), 1350 m alt.; Kamiali Wildlife Manage- ment Area, nr Blue Mt, Takeuchi et al. 21068 (L).

Notes — This species is distinctive by the basally connate, dark maroon outer petals and the high number of stamens. Zygogynum cruminatum has also many stamens, but its numerous petals are free and the number of carpels is much higher. A large, still closed bud of Clemens 4596 showed an aberrant state for the stamens: the thecae were already open, those of the higher stamens widely open, those of the lower stamens just opening. In this case the flower is not protogynous as is usual in the family, and stamen dehiscence is centrifugal instead of the usual centripetal mode. The carpels in this bud were developed normally.

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.).