Syzygium lampeapiense Sunarti & Rugayah

Sunarti, Siti, 2024, Two new species of Syzygium (Myrtaceae) from Wawonii Island, Southeastern Sulawesi, Indonesia, Phytotaxa 661 (1), pp. 87-96 : 88-91

1. Syzygium lampeapiense Sunarti & Rugayah , sp. nov.

TYPE:— INDONESIA, Southeast Sulawesi, Wawonii Island, Lampeapi, 28 April 2004, Rugayah 1004 (holotype BO 1993392!, isotypes BO 1993393!, 1993394!, SING!). Figures 1 , 2 A–E , 3 .

Diagnosis:— This species is similar to S. comosum Widodo (in Widodo & Chikmawati 2016: 6) from Payakumbuh, Sumatra, especially in its rheophytic habits and solitary flowers in general, but differs in its young twigs and leaf arrangement, the presence of oil dots on the leaf surfaces, the hypanthium and the pedicel. Syzygium lampeapiense has slightly sub-terete young twigs with internodes are 12–15 mm long and leaves loosely arranged along the branches, the petioles usually forming angles about 60° with the branches, while S. comosum has 4-angled young twigs with internodes 5–10 mm long and leaves densely arranged towards the tip of the branches, the petioles forming angles about 30° with the branches. The upper and lower leaf surfaces of S. lampeapiense have numerous oil dots (10–15/ mm² lower and 27–30/mm² upper), while S.comosum has few oil dots (0–7/mm² lower, and 8–12 mm ² upper). This species has more flexible leaves, while S. comosum has more rigid leaves. Flowers of S. lampeapiense bear pedicels to 5.5 cm long and present obconical hypanthium, while those of S. comosum have pedicels to 1 cm long and a funnel-shaped hypanthium. It is also similar to the Bornean rheophytic species Syzygium medium ( Korthals 1847: 199) Merril & L.M.Perry (1939: 166) , but differs by its leaves 4–11.5 × 1.5–3 cm with one intramarginal vein and flowers with obconical hypanthium and styles 2.8–3.5 cm, while S. medium has leaves 0.6–11 x 0.4–1.1 cm with 2 intramarginal veins and flowers with hypanthium funnel-shaped and styles to 1.4 cm long.

Description:— Rheophytic tree to 5 m tall, diameter at breast height (dbh) 10 cm. Twigs slightly flat-terete. Leaves opposite, decussate; blades elliptic to narrowly elliptic, (4–)6–11.5 × (1.5–) 1.7–2.5(–3) cm; apex acuminatecuspidate (tip 5–12 mm), base attenuate-cuneate; midrib on the upper surface slightly raised along a furrow, raised on the lower surface; secondary veins 9–12 pairs, straight and curved, forming an angle of 40° with midrib, raised on the lower surface; upper surface has 27–30/mm² and lower surface has 10–15/ mm² oil dots; intramarginal vein 1, ca. 1 mm from the leaf margin; petioles 4–7 mm long, 1 mm thick, on the upper surface slightly grooved. Inflorescences terminal or axillary, mostly uniflorous; pedicels 3–5.5 cm. Flower buds obconical (12–16 mm long, 9–11 mm diam.) with oil dots on outer surface. Flowers with hypanthium obconical, 13–17 mm long, with numerous oil dots, greyishred; sepals four, free, to 5 × 7 mm, obovate, persistent along anthesis, membranous, glandulose in the medial portion; petals four, free, to 12 × 9 mm, membranous, glandulose in the medial portion, white, soon falling after anthesis. Stamens numerous (217 in one flower counted); filaments to 2.5 cm long, white; anthers basifixed, white. Style 2.8– 3.5 cm, greenish. Ovary 2–locular. Fruits unripe, globose, 1.6–2 cm diam.; greyish-rose until yellowish green, with numerous oil dots.

Distribution:— Wawonii Island (Lampeapi, Wungkolo, Dompo-dompo Jaya), Southeast Sulawesi, Indonesia. Besides the specimens examined, a photograph taken by Wiriadinata along the riverbanks of Roko-roko in the Dompo-dompo Jaya area identified by him as Syzygium sp. (Wiriadinata & Hamzah 2006: 49) represents the species here described as S. lampeapiense .

Habitat and ecology:— vegetation on riverbanks along river.

Flowering and fruiting:— April.

Vernacular name:— pe api.

Etymology:— The specific epithet refers to the name of a village in Wawonii island where the species was first collected.

Preliminary conservation assessment:— VU B2a (Vulnerable). This species is found in a small island, distributed at only three fragmented locations. Even though the species still has a large population (growing along the Lampeapi river site) and there was no threat observed at that moment, nickel mining may represent a possible future threat for it.

Paratype:— INDONESIA, Wawonii Island, Wungkolo, 30 April 2006, Arief Hidayat 1313 (BO!).

Note:— Syzygium lampeapiense was listed in Rugayah et al. (2015: 206) as Syzygium sp. 1 .

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 2. Syzygium lampeapiense: flowers (A), fruits (B), lower leaf surface (C), upper leaf surface (D), flower bud (E); S. comosum: lower leaf surface (F), upper leaf surface (G), flower bud (H).

FIGURE 3. Type specimen of Syzygium lampeapiense.