Syzygium komatiense Byng & Pahlad., 2016

Byng, James W. & Pahladsingh, Fareiza R., 2016, Syzygium komatiense (Myrtaceae), a new species from South Africa, Phytotaxa 272 (1), pp. 97-100 : 97-99

Syzygium komatiense Byng & Pahlad. , sp. nov. Type:— SOUTH AFRICA: Mpumalanga, next to Komati River , near bridge, 25 November 2010 (fl.), J.W. Byng 68 (holotype WAG!; isotypes K!, PG!, PRE!). Figures 1 , 2 .

The species is similar to Syzygium guineense ( Willdenow 1799: 974) Candolle (1828: 259) but differs in the often asymmetric or oblique leaf base, less prominent tertiary venation, less pronounced intramarginal vein and shorter, fewer-flowered inflorescences.

Glabrous tree, 4 ‒ 15 m; stem upright and straight or crooked and reclining over water; bark smooth, pale grey to white. Branchlets terete, pale grey to light brown. Leaves coriaceous, drying dark olive green above and sometimes turning brown, pale green below, matte on both sides. Petiole 8 ‒ 18 mm long, slender, pinkish-orange when young, 1–2 mm diameter. Blades 5.3 ‒ 10.6 × 2 ‒ 4.7 cm, elliptic, ovate or lanceolate-elliptic; base obtuse to attenuate, frequently asymmetrical or less often oblique; apex acute or subacuminate, margin flat or wavy; 10 ‒ 13 secondary vein pairs, 4–12 mm apart, prominent on both sides, tertiary veins few to many, faint; inner intramarginal vein 1–3 mm from leaf margin, obscure, outer intramarginal vein absent. Bracts ca. 0.5 mm, deltoid, persistent; bracteoles ca. 1 mm, deltoid, persistent. Inflorescences terminal, up to 3.6 cm long, axes angular to subterete, flowers up to 8, in clusters of 2–4. Flowers 9–11 mm long at anthesis, buds ca. 3 mm in diameter, pseudostalk absent or ca. 1 mm in median flower. Hypanthium 4–6 × 4–5 mm, obconical to slightly pyriform, yellowish-green. Calyx lobes four, 1–1.5 × ca. 1 mm, semi-circular, greenish-yellow. Petals four, ca. 2–3 × 2 mm, orbicular, white. Stamens 5 ‒ 8 mm, white; anthers ca. 0.5 mm. Style 4 ‒ 6 mm, simple, white. Fruits ca. 2 × 1.1–1.3 cm, oblong to urceolate, dark purple when maturing.

Distribution and habitat:—Confined to the Komati River system on the South Africa-Mozambique border ( Figure 2 ). No records are known from Mozambique but the species is highly likely to be present in the country.

Habitat and ecology:—Riparian forests, in water or hanging over water; 0 ‒ 250 m elev.

Paratypes:— SOUTH AFRICA. Mpumalanga: Komatipoort River near bridge, 7 August 1998, M. Lotter 357 (LYD!) ; banks of the Komati River, at the bridge on the Hectorspruit / Coopersdal road, April 1999, W. McCleland 439 (LYD!) ; Komati River, Tonga / Shongwe area , 6 February 2001 (fr.), Burrows & Schmidt 7266 (BNRH!) ; Komatipoort , 30 September 1906 (fl. bud), F.A. Rogers 3038 (PRE!) ; banks of Komati River at Turley’s Drift, West of Komatipoort , 21 February 1978 (fr.), D. McMurtry 2410 (PRE!) .

Etymology:—The species is named after its type locality, the Komati River.

Conservation status:— Syzygium komatiense is only known from a few mature individuals in the Komati River system with an Extent of Occurence (EOO) of 62.630 km 2 and an Area of Occupancy (AOO) of 16 km 2. Given that the species is highly restricted along the Komati River outside nature reserves and under threat from anthropogenic activities, such as encroachment of housing, bridges and use of the wood for timber, it is assigned a preliminary status of Critically Endangered (CRa(i,ii); D) according to the IUCN Red List Criteria ( IUCN 2001).

Notes:—The species was previously thought by Schmidt et al. (2002) to be associated with S. guineense subsp. barotsense F.White ( White 1962: 455) based on its riparian habitat and its pale grey to white bark. However, it differs from this subspecies in the oblong and wholly purple fruit, larger leaves, variable leaf base, more widely spaced secondary venation and fewer flowered inflorescences. It differs from S. guineense subsp. guineense by the general characters highlighted in the diagnosis. Molecular data also support that S. komatiense is unrelated to S. guineense s.l. (Byng unpublished data). Syzygium komatiense seems restricted to the Komati River system and more samples are required to assess whether it is more widespread.

Figures

FIGURE 1. Syzygium komatiense Byng & Pahlad. A bark; B petioles; C frontal view of inflorescence; D side view of inflorescence; E fruits; F flowering branch of type material. (A–D, F Byng 68; E Burrows & Schmidt 7266. Scale bar = 1 cm).

FIGURE 2. Distribution map of Syzygium komatiense Byng & Pahlad.