Zygogynum longifolium (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 : 46-47

8. Zygogynum longifolium (A.C.Sm.) Vink — Fig. 1 , 3

Zygogynum longifolium (A.C.Sm.) Vink (1985) 53. — Bubbia longifolia A.C.Sm. (1942) 429. — Type: Brass 13868 (holo A).

Bubbia monocarpa A.C.Sm. (1942) 428. — Type: Kanehira & Hatusima 12105 (holo A; iso BO).

Drimys monogyna Kaneh. & Hatus. (1943) 147, f. 17. — Type: Kanehira & Hatusima 12105 (holo FU n.v., photo in L; iso A, BO).

Drimys oligocarpa Diels (1924) 79, non Schltr.

1 mm

Shrub or treelet 1.5–4.5 (or more?) m high, dbh up to 10 cm, little branched. Branchlets rather slender to stout, light to greyish brown, often with myrmecodome. Leaves crowded at the end of branchlets; petiole 5–10(–15) mm long, almost flat above, rounded below, blackish; blade obovate to oblanceolate, 17–43 by 5.5–15 cm, (thick) chartaceous, said to be bullate in vivo ( Takeuchi 11084), in sicco (light brown to) purplish grey below; apex obtuse to acute and ultimately up to 1.5 cm rounded broad-acuminate, base sometimes with recurved margins, (narrowly) acute; midrib impressed above, strongly prominent below; secondary nerves at 50–80° with midrib, arcingly joined at some distance from margin, distinct above, prominulous to prominent below. On lower leaf surface stomata white, in short strings, or forming a labyrinth, not over secondary nerves; oil cells scattered, rarely indistinct. Inflorescences with 2 – 6 partial inflorescences, these 8 –18 cm long, sometimes pendulous, with very slender axes, 6–30-flowered, flowers inserted on axes (1st or) 2nd to 3rd (to 6th) order; empty bracts below inflorescence 0 – 4; pedicels 1–12 mm, in fruit up to 20 mm long, slender. Calyx 2–3 (or 4-, or irregularly) lobed, 1–2 mm long, thin, smooth. Petals 4–6(–7), free, elliptic to obovate, greenish red to very dark red, outer ones 3.5–6 by (1.5–) 2–3.5 mm, inner ones if present 4.5–6 by 2.5–3 mm, apex (broadly) rounded. Stamens 11–21, 1.5–3.5 mm long, filaments often inflated, red or olivaceous; thecae apically slightly separate to touching; connective not prolonged; pollen in tetrads. Carpels (1–)2–3(–4), free, 1.5–3 by 1–2 by 1–1.5 mm, green; stigma (almost) as long as carpel apex or slightly longer at one or both ends or slightly descending adaxially; ovules 10–32. Fruitlets a soft berry, globose, pink, orange or red, in sicco usually strongly flattened and in centre showing seeds, 14– 25 mm diam; base usually abruptly obconical, sometimes with up to 1.5 mm long distinct stipe, or rounded; fruitwall without brachysclereids; placenta sometimes strongly plate-like enlarged; pulpa in thin layers between the seeds and following seed sculpture but usually not completely enveloping seeds. Seeds several to many (c. 5–16), obovoid and narrowed to constricted in lower part, 5–7.5 by 2.5–4.5 by 2–3.5 mm; testa thin, brittle, (brownish) grey to dull black, pusticular, or pusticular and apically with tendency to ribs, or with thin irregular flanges.

Distribution — Papua, Japen I. to PNG, Bismarck Ra.

Ecology — Rainforest at 60–540 m altitude. Flowering March, July–September, fruiting (April) July–October.

Lam (1928, 1945) gives a description of the lowland forest of his collection site at Prauwenbivak ( Lam 794, as Drimys oligocarpa , det. Diels; 110 m alt.). Kanehira & Hatusima (1943) refer to Agathis­ forest; the localities on Japen I. and on the Sidoarsi Mts are also in or close to Agathis­ forests. Agathis often occurs on ultrabasic soils.

Galls — Zygogynum longifolium is one of the few species with myrmecodomes in the twigs.

The sterile collection Vink 17494 from Lei R. on the W side of the Doma Peaks looks like the present species, but the altitude of 2780 m is very aberrant. One leaf of this collection has on the lower side a 10 cm long row of 11 galls and 5 scars of galls. These galls are globose, c. 3.5 mm diam, brown when dry, densely pusticular, and subapically with a double line reminding of a stigma (but without stigmatical papillae). On the upper side of the leaf the insertions of the galls are visible as slightly raised rings c. 2 mm diam.

Specimens examined. INDONESIA, Papua,Kab. Yapen-Waropen,Japen I., Woda, Koster BW 11194 (L, LAE ), 11196 (K, L, LAE ), 60 m alt.; ibidem,Soemboi R. near Seroei, Aet & Idjan 539 (A, BO, L, PNH, SING); Kab. Nabire, Nabire area,Dallman R., Kanehira & Hatusima 12105 (A,BO, FU n.v.), 500 m alt.; Napan Dist., Akama, Ijiri & Niimura 464 (L); Kab. Sarmi, Sidoarsi Mts, Vink BW 8413 (A, K, L), 200 m alt.; Kab. Jayawijaya,Idenburg R., Feuilletau de Bruyn 50 (BO, L), 60 m alt., ibidem, Prauwenbivak, Lam 794 (BO, L, U), 1165 (L), 1225 (BO, L), 120 m alt.; Bernhard Camp, Brass 13868 (A), 175 m alt.; ibidem,Pagai (‘Mamberamo R.’), Sauveur 3005, 3005a (L). – PAPUA NEW GUINEA, East Sepik Prov., Ambunti Subprov., Yapa (Hunstein) R., Hoogland & Craven 10535 (A, L), 120 m alt.; Hunstein Ra., Takeuchi 6064 (L), 125 m alt.; Prince Alexander Ra., Maprik, Robbins 2004 (CANB), 540 m alt.; Pas- sam Rd off Wewak-Maprik Rd, Robbins 2131 (CANB), 300 m alt.; Madang Prov., Bismarck Ra., Takeuchi 11084 (L), 600 m alt.

Doubtfully this species: PAPUA NEW GUINEA. West Sepik Prov., Bewani Subprov., Bewani, Wiakabu LAE 73772 (L), 160 m alt.; S. Highlands Prov., Tari Subprov., Lei R., 2780 m alt., Vink 17494 (A, BO, CANB, L, LAE ).

Notes

– Petal arrangement. The arrangement of the petals shows a peculiar variation. If 4 or 6 petals are present, these are inserted in two alternating pairs or as two triplets, but 6 petals can also be arranged as 4 outer and 2 inner ones. In Z. schramii the 6 petals are all inserted in a single row, with any additional petal in a second series.

– Stamens. Wiakabu LAE 73772 deviates by its high number of stamens: 33–36 vs 11–21 in the other specimens.

– Seeds. In the specimens from Japen I. at the western end of the distributional area the seeds are pusticular and have only a few ribs or very short flanges, whereas in the specimens from the mainland the seeds have distinct, thin, irregular flanges (Smith: ‘plicate-rugose’). Smith described the seeds as 7–9 by 5 mm, but I have seen no seeds longer than 7 mm in the material seen by him.

Bubbia monocarpa and Drimys monogyna are described on duplicates of the same collection; it differs from the other material only in the lower number of carpels: usually one, sometimes two, a condition also encountered in Z. schramii .

For comparison with Z. schramii , also from the Sidoarsi Mts,

see there. Zygogynum montanum from Papua New Guinea is similar (also with myrmecodomes reported), but it lacks the purplish leaf colour, it has a shorter stigma, and smooth seeds.

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.).

Fig. 3 a.Zygogynum cyclopensis Vink.Seed, lateral. — b, c. Z.longifolium (A.C.Sm.) Vink.Seed from lateral and abaxial sides resp.(a:Van Royen & Sleumer 6396; b, c: Takeuchi 11084).