Syzygium wawoniense Sunarti & Rugayah

Sunarti, Siti, 2024, Two new species of Syzygium (Myrtaceae) from Wawonii Island, Southeastern Sulawesi, Indonesia, Phytotaxa 661 (1), pp. 87-96 : 91-94

2. Syzygium wawoniense Sunarti & Rugayah , sp. nov.

Type:— INDONESIA. Southeast Sulawesi, Wawonii island, Langkororo, 28 April 2004, Rugayah 1014 (holotype BO 1993395!, isotypes BO 1993396!, 1993397!, SING!). Figures 1 , 4A–D , 5 .

Diagnosis:— This species is similar to S. ketambense Widodo (in Widodo & Chikmawati 2016: 9) in its inflorescences and flowers, but differs in its hypanthium and leaves. Hypanthia of this species are up to 7 mm and the tip is rounded to obconical, while in S. ketambense they are longer than 13 mm and the tip is elongate. The stamens of S. wawoniense are about 250 and up to 3.5 cm long, while in S. ketambense they are about 160 and up to 1.2 cm long. The innermost intramarginal vein in S. wawoniense is up to 11 mm from the margin, while in S. ketambense it is ca. 3 mm from the margin. The abaxial surface of the leaves of S. wawoniense present 70–75 oil dots / mm², and the adaxial ones 70–80/ mm², while in S. ketambense the abaxial surface presents 0–8(–12) oil dots / mm² and the adaxial ones 0–6(–10) mm² oil dots.

Description:— Trees up to 10 m tall, with diameter at body height to 10 cm. Twigs terete. Leaves opposite, decussate, blades elliptic-ovate, 10.5–22.7 × 4.4–7.4 cm; margin entire; base cuneate to slightly rounded, apex acute to acuminate (4–10 mm); midrib on the upper surface sunken, raised on the lower surface; secondary veins 7–10 pairs, arching, forming angles 60°–70° with midrib, raised on the lower surface; upper surface glabrous, with 70–80 oil dots / mm²; lower surface glabrous, with 70–75 oil dots / mm²; two intramarginal veins, the inner one 5–11 mm from the margin, the outer one 1 mm from the margins; petioles 7–11 mm long, 1.5–2.5 mm thick, dark brown when dry, slightly swollen, furrowed on the upper surface. Inflorescences terminal or axillary on the terminal part, 6.5–17 cm long, with 3–16 flowers; pedicels slender, 2.5–6.5 cm long, 0.5 mm in diameter. Flowers with hypanthium funnel-shaped, 5–7 mm long, green; sepals four, free, persistent, 4.5–7 mm long × 5–10 mm wide, broadly ovate, margin membranous, glandulose, curved, green; petals four, free, 7–12 × 8–10 mm, with claw, white, the margin membranous, soon lost after anthesis. Stamens numerous (260–550); filaments 2–3 cm long, white; anthers yellow. Style ca. 3.2 cm, greenish white. Ovary 2-locular. Fruits unknown.

Distribution:— Wawonii Island (Langkororo, Wungkolo), Southeast Sulawesi, Indonesia.

Habitat and ecology:— Forest, at about of 100 m elev.

Vernacular name:— Mongupadahu.

Flowering:— April.

Etymology:— The specific epithet refers to the name of the island where specimens were first collected.

Preliminary conservation assessment:— ER B2a D (Endangered). This species was collected in a small island, distributed at three closely fragmented locations and rarely found. Additionally, nickel mining may possibly represent a future threat for the species.

Note:— The type of Syzygium wawoniense is one of the two specimens listed as Syzygium sp. 2 in Rugayah et al. (2015: 206). The second specimen cited, Hidayat 1406 (BO!), reminds S. wawoniense but pedicels are shorter and wider (1–2 cm long × 1 mm in diam. versus 2.5–6.5 cm long × 0.5 mm in diam. in S. wawoniense ).

Figures

FIGURE 1. Location of plant exploration and distribution of Syzygium lampeapiense (●) and S. wawoniense (■) P. Sulawesi (sources: Berkas:Sulawesi blank map.png - Wikipedia bahasa Indonesia,ensiklopedia bebas id.m.wikipedia.org); P.wawonii (sources: Bakosurtanal. Edisi 1-1992 & Google Map (02 Maret 2015).

FIGURE 4. Syzygium wawoniense: inflorescence (sources: Rugayah et al. 2019) (A), lower leaf surface (B), upper leaf surface (C), flower bud (D); S. ketambense: lower leaf surface (E), upper leaf surface (F), flower bud (G).

FIGURE 5. Type specimen of Syzygium wawoniense.