Syzygium quoctrianum, Soh & Sam & Parnell, 2024

Soh, Wuu Kuang, Sam, Hoang Van & Parnell, John A. N., 2024, Three new species of Syzygium Gaertn. (Myrtaceae) from Cambodia and Viêtnam, Adansonia (3) 46 (4), pp. 29-36 : 30-32

Syzygium quoctrianum

W.K.Soh, H.V.Sam & J.Parn., sp. nov.

( Fig. 1 )

Similar to Syzygium lineatum (DC.) Merr. & L.M.Perry in the narrowly spaced secondary veins, the straight and close to the margin intramarginal veins and the long conical hypanthium, but differs in having relatively small leaves ( S. quoctrianum sp. nov.: 3-5.5 × 2-3 cm; S. lineatum : 6-9 × 2.2-4.5 cm), a revolute leaf margin ( S. lineatum : flat margin), the first order branching inflorescence ( S. lineatum : second order branching inflorescence) and the sessile flowers ( S. lineatum : pedicellate flowers).

TYPE MATERIAL. — Viêtnam • Khánh Hòa province [Nhatrang]; 1800 m a.s.l.; 21.V.1922; Poilane 3572; holo-, P [ P04460694 ]!, iso-, P [ P06666932 ]!).

ETYMOLOGY. — This species is named in recognition of Mr Nguyen Quoc Tri, Deputy Minister, Ministry of Agriculture and Rural Development Vietnam, who has done so much to promote sustainable forest management in the country.

DISTRIBUTION. — Endemic to Viêtnam, so far known only from the type locality in Khánh Hòa province.

HABITAT. — A highland species, documented in shrubby vegetation on moist peaty soil, at 1800 m elevation hence on a dwarf montane forest.

PHENOLOGY. — Collected in flower in May.

CONSERVATION STATUS. — DD (Data Deficient) ( IUCN 2012). The locality in the herbarium label is stated as ‘Nhatrang’ which most probably refers to the province Khánh Hòa rather than the capital Nhatrang which is in the lowlands since the specimen was collected at 1800 m a.s.l. The landscape above 1000 m a.s.l. in Khánh Hòa province appears to be forested on satellite imagery in Google Earth (images taken between 2018 and 2021). However an accurate location of the collection point is unknown. Further information on location, population size and habitat quality are needed.

DESCRIPTION

Tree, 4 m tall, trunk 7.9 cm diameter, glabrous. Twig terete, c. 3 mm diameter, stout, surface smooth, whitish to brownish, not contrasting to leaf colour, young twig angular. Leaves opposite, coriaceous to subcoriaceous, greenish-brown, dark green in vivo, 3-5.5 × 2-3 cm, 1.5-2 times as long as wide, elliptic, base cuneate, margin revolute, apex acuminate, acumen distinct, 0.2-0.4 cm long, 1/10-1/20 of blade length, recurved; midrib sunken above, raised below; secondary veins very slender, 11-16 per side, 2-4 mm apart, 65-70 degrees from midrib, faint, raised above and below; tertiaries faint, reticulate; intramarginal veins 0.5-1 mm from margin, straight, margin revolute; petiole 0.4-0.8 cm long, 1/14-1/5 of blade length, c. 1 mm diameter, slender, brownish, not contrasting to blade colour. Inflorescence terminal, 2-3 cm long (not including stamens), paniculate, first order branching, flowers to 15 flowers; main axes c. 8 mm long; bracts and bracteoles caducous, c. 1 mm long. Flower greenish white in vivo, fragrant in vivo, sessile, hypanthium not glaucous, not fibrous, 6-7.5 × 4.5-5 mm, conical, pseudostalk indistinct; sepals 4, free, 2-2.5 × 3-4 mm, semiorbicular; petals 4, free, 4.5 × 6 mm, not coherent, semiorbicular; outer stamens c. 1.5 cm long, anther sacs parallel, connective gland conspicuous; style c. 12.5 mm long, ovules 8 per locule, irregularly radiating. Fruit not seen.

Figures

FIG. 1. — Syzygium quoctrianum W.K. Soh, H.V.Sam & J.Parn., sp. nov.: A, flowering branch; B, flower bud; C, longitudinal section of mature flower; D, leaf ve- nation. Poilane 3572. Scale bars: A, 1 cm; B, C, 5 mm; D, 2 mm. Drawn by Wuu Kuang Soh.