Syzygium devogelii Brambach, Byng & Culmsee, 2017

Brambach, Fabian, Byng, James W. & Culmsee, Heike, 2017, Five new species of Syzygium (Myrtaceae) from Sulawesi, Indonesia, PhytoKeys 81, pp. 47-78 : 62-64

3. Syzygium devogelii Brambach, Byng & Culmsee sp. nov. Figures 4 , 5 , 8

Myrtaceae " sp. 10" p.p. ( Culmsee and Pitopang 2009, see also 2017 (Erratum)).

Diagnosis.

Syzygium devogelii is a species of treelets characterised by slender, narrowly winged young branchlets, medium-sized narrowly elliptic leaves, straight and distinct secondary veins connected by an intramarginal vein impressed above and prominent beneath, small flowers (5 × 3 mm in bud) in terminal inflorescences that develop into rather large fruits (c. 20 × 25 mm), mature seeds lacking a testa, and cotyledons with echinate outer surfaces. The species is morphologically similar to Syzygium perspicuinervium (Merr.) Masamune (1942, 537) but differs from that species in smaller leaves with fewer secondary veins and in flowers with distinct calyx lobes (vs calyx calyptrate). It is furthermore similar to Syzygium valdevenosum (Duthie) Merrill and Perry (1939, 182) but differs in lateral veins which are impressed above (vs prominent), much smaller inflorescences, and smaller, obconical (vs infundibuliform) flowers. Floral formula B1 Bt2 K4* C4* A∞* Ĝ (2)┼ Vx∞.

Type.

INDONESIA. Central Sulawesi (Sulawesi Tengah), LLNP, Kab. Poso, Kec. Lore Utara, west slope of Mt Rorekautimbu , c. 1°17.5'S 120°16.3'E, 1350 m, 11 May 1979: de Vogel EF 5293 (fruits; holotype L [L.2535665]! [L.2535666]!; isotype K!) .

Description.

Trees, up to 13 m tall, diameter at breast height ≤ 13 cm, trunk ≤ 7 m tall. Outer bark whitish to brown, mealy or peeling off in thin sheets, inner bark pale or dark red, wood cream-coloured. Young branchlets 1-2.5 × 2-3 mm, ± flattened, angular or oblong in cross section with 4 narrow wings, epidermis dark red when young, drying reddish or yellowish brown, smooth; becoming rounded with 4 ridges, bark (yellowish) brown, peeling off in thin sheets.

Leaves (sub-)opposite. Petioles 7-16 × 1-3 mm, channelled above, rounded beneath, epidermis drying smooth or with transverse cracks. Blades (12.5-) 14-19 (-22.5) × (4-) 4.5-7 (-8.5) cm, ratio (2.1-) 2.6-3.3 (-4), narrowly elliptic (or lanceolate), base cuneate or obtuse, apex acuminate, margin revolute; chartaceous or coriaceous, red or pink when young, above, beneath, drying dull to satin, variable in colour from greyish brown and olive grey to very dusky red above, dull to satin and, dark reddish brown beneath; pellucid dots rather few, visible or not on both sides. Midrib channelled above, very prominent, rounded, smooth and drying darker than the lamina beneath. Secondary vein pairs (9-) 11-14 (-17), 5-22 mm apart, channelled or impressed above, prominent and drying darker than the lamina beneath, straight or slightly arching from the midrib; intersecondary veins sometimes present. Tertiary veins dense, ± ladder-like and perpendicular to the midrib, faint above, prominulous beneath. Inner intramarginal vein 2-9 mm from leaf margin, looping or not and prominent; outer intramarginal vein 0.5-1.5 mm from leaf margin, as prominent as tertiary venation.

Inflorescences terminal, dense metabotryoids, 2.5 cm long, peduncles 1 cm long, axes flattened, with 2 or 4 narrow wings, drying brown. Bracts c. 1.5 mm long, ovate, keeled, caducous; bracteoles 2 per flower, 1 mm long, similar to bracts.

Flowers c. 15 per inflorescence, within the inflorescence in triads, 4-merous, anthopodium absent, only known before anthesis, mature buds 5 × 3 mm. Hypanthium c. 4 × 3 mm, obconical, drying dark reddish brown, densely glandular-warty, hypanthium rim 2 mm long, glandular inside. Calyx lobes c. 1 × 2 mm, broadly rounded. Petals c. 3 × 3 mm, cucullate in bud. Stamens c. 100, filaments 2-3 mm long, anthers c. 0.4 mm long, ellipsoid. Ovary bilocular, surrounded by spongy tissue, ovules numerous per locule, ascending. Style 3-4 mm long, pointed.

Fruits 1-seeded, c. 20 × 25 mm, irregularly depressed globose, laterally compressed, green, drying black and, smooth, pericarp ± woody, 1 mm thick, hypanthium rim 1-2 mm long, 5-9 mm in diameter.

Seeds c. 15 × 20 mm, transverse ellipsoid, testa adhering to the pericarp, spongy inside and adhering to the outer surface of the cotyledons, cotyledons ± half-globose, facing surfaces undulate, outer surfaces densely echinate, protuberances obscured by spongy testa tissue.

Etymology.

The species is named after Eduard Ferdinand de Vogel (*1942). Ed de Vogel is a renowned authority on Malesian orchids, especially those from New Guinea. His contributions to the flora of Sulawesi are perhaps less well known: with almost 2000 specimens of excellent quality collected there in 1973-74 and 1979 - among them the type specimen of this species - he was one of the most prolific plant collectors on the island during the 20th century.

Phenology.

Flowering was recorded in August, fruiting in May.

Distribution and habitat.

Syzygium devogelii is endemic to the province of Central Sulawesi, currently known to occur in lower montane forest at two localities in LLNP from 1350-1400 m elevation (Figure 4 ). In the Bariri NE inventory plot, it was fairly common, growing on mid-slope terraces with Rhodic Ferralsols ( IUSS Working Group WRB 2014) derived from acid plutonic rocks. The forest there was dominated by Fagaceae , Myrtaceae , Burseraceae , Lauraceae , and Elaeocarpaceae (families with top five FIV) and contained six other species of Syzygium : S. acuminatissimum , S. aff. baeuerlenii (F.Muell.) Craven and Biffin (in Craven et al. 2006, 135), S. lineatum , S. zeylanicum (L.) de Candolle (1828, 260), and two undetermined species ( Brambach et al. in press). See Culmsee and Pitopang (2009) for more information on the floristics of the Bariri forest.

Conservation status.

Syzygium devogelii has a limited geographical distribution and seems to be restricted to lower montane forest within a narrow elevational belt. Known from only two localities, the EOO and AOO cannot be estimated reliably for the species. Because of the low collection density in Central Sulawesi, we believe that the species is more widespread and common than it currently appears. Deforestation has been recorded close to the type locality (using the Global Forest Change website, Hansen et al. 2013). Given the apparent narrow geographical and elevational distribution, ongoing deforestation and the recommendation to use a precautionary attitude in conservation assessments ( IUCN Standards and Petitions Subcommittee 2014) we propose a preliminary extinction risk assessment of “Endangered” (EN B1ab(i,ii,iii)).

Notes.

Most species of Syzygium are reported to have cotyledons with rather smooth outer surfaces, unlike the peculiar echinate cotyledons of S. devogelii . We here interpret the tissue covering the outer surface of the cotyledons (Figure 5 ) and obscuring its protuberances as derived from the testa, as reported for the Australian species Syzygium bungadinnia (F.M.Bailey) Hyland (1983, 64), but closer examinations of fruit and seed structures are necessary to corroborate this interpretation.

Juvenile specimens of Syzygium balgooyi are similar to S. devogelii in their leaf shape, colour, and venation. In fact, both species were treated as one morphotype in Culmsee and Pitopang (2009, 2017). Besides the very different flowers, they can, however, be distinguished by the shape of the young branchlets: strongly flattened and with rounded ridges in S. balgooyi (Figure 1e ) vs ± flattened with 4 narrow wings in S. devogelii (Figure 5 ).

Additional specimens examined

(Paratypes). INDONESIA. Central Sulawesi (Sulawesi Tengah) , LLNP, Kab. Poso, Kec. Lore Tengah: 9 km NW of Bariri, 100 m east of climate tower, tree-inventory plot Bariri NE, 1°39.4'S, 120°10.5'E, 1400 m, 9 Sep 2006: Culmsee H 1333 (sterile; BO [BO-1938455]!, CEB) & 1378 (sterile; CEB, K [K000993491]!); ibid. loco, 18 Aug 2011: Brambach F, Mangopo H, Firdaus, Faber M, Tiranda R 0818 (sterile; BO [BO-1938442]!, CEB, GOET [GOET020015]!) & 0845 (sterile; BO [BO-1938443]!, CEB, L!) .

9 km NW of Bariri, 80 m south of climate tower, tree-inventory plot Bariri S, 1°39.5'S, 120°10.4'E, 1400 m, Jul 2006: Culmsee H 1252 (sterile; CEB, GOET [GOET020016]!) & 1564 (flower buds; CEB, L!) .

Figures

Figure 1. Morphological characters of Syzygium balgooyi and S. schumannianum. Syzygium balgooyi (a-k): a c. 20 m tall trunk b upper leaf surface; c lower leaf surface d bark with slash e ridged shoot apex with subopposite leaves f flowers at different stages during anthesis and fruit g trunk base with steep narrow buttresses h inflorescence with flower buds i shoot with young leaves j dried flowers before and during anthesis and longitudinal section of flower k dried fruit and longitudinal section of fruit showing two cotyledons. Syzygium schumannianum (l-m): l dried flowers before and during anthesis m dried fruit. a-b and h-i Brambach et al. 1564 c Brambach et al. 0861 d-e Brambach et al. 0628 f sighting on Mt Katopas by FB g Brambach et al. 0889; j holotype van Balgooy 3956 [L. 2517558] k de Vogel 5413 [L. 2517563] l Wiakabu et al. LAE 50571 [L. 2535534] m Brass 13610 [L. 2524420]. All scale bars: 1 cm.

Figure 4. Distribution map of four species of Syzygium in Central Sulawesi: Syzygium contiguum (orange diamonds), S. devogelii (yellow dots), S. eymae (light blue square), and S. galanthum (green triangles). Lore Lindu National Park is indicated by a black line. Map created with QGIS (QGIS Development Team 2016) using the digital elevation model of Jarvis et al. (2008).

Figure 5. Syzygium devogelii: a leafy twig with fruit b longitudinal section of ripe fruit with inner, flat side of cotyledon and echinate outer surface c flower bud, longitudinal section d flower bud, exterior view. a-b holotype de Vogel 5293 c-d Culmsee 1564.

Figure 8. Leaves of all new species described. Variation of Syzygium balgooyi (a-e), S. contiguum (f), S. devogelii (g), S. eymae (h), and S. galanthum (i). a Brambach et al. 0283 b Brambach et al. 0681 c Brambach et al. 1333 d de Vogel 5413 [L. 2517563] e Culmsee r 2162 f Culmsee r 463 g Brambach et al. 0818 h Eyma 3624 [L. 2535689] i Brambach et al. 0533. Scale bar: 10 cm, valid for all leaves.