Syzygium eymae 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 : 64-67

4. Syzygium eymae Brambach, Byng & Culmsee sp. nov. Figures 4 , 6 , 8

Diagnosis.

Syzygium eymae is characterised by small (usually 2.3-4 × 1.5-2.5 cm), (sub-)sessile, leaves with thickly coriaceous, (broadly) elliptic or obovate blades, dense terminal inflorescences, and small, pyriform flowers with a calyptrate calyx that bears a minute apical opening and splits irregularly at anthesis. It differs from the morphologically similar Syzygium paradoxum (Merr.) Masamune (1942, 536) in angular young branchlets (vs terete), leaves without conspicuous gland dots (vs leaves conspicuously gland-dotted beneath), fewer pairs of secondary veins (5-7 vs 10-14), and smaller (5-6 × 3 vs c. 12 × 5 mm in mature buds), pyriform flowers without anthopodia (vs infundibuliform with anthopodia 5-7 mm long). Floral formula B1 Bt2 (K4?* C4?*) A∞* Ĝ (2)┼ Vx?.

Type.

INDONESIA. Central Sulawesi (Sulawesi Tengah), Kab. Tojo Una-Una, Border of Kec. Ulubongka and Kec. Ampana Tete, Mt Lumut , between summit and western secondary peak, c. 1°12.3'S, 121°47.6'E, ± 2200 m (" Selebes, Res. Menado. O. afd. Poso. G. Lóemoet, Pilaartop en W. bijtop. (summit)") , 5 Sep 1938: Eyma 3624 (flowers; holotype U [U.1439024]!; isotypes: BO [BO-1679767]!, L [L.2535689]!).

Description.

Trees, height, bark and wood unknown. Young branchlets slender, 0.5-1 × 1-2 mm, rectangular in cross section, ridges arising at the petioles and running downwards to next node, epidermis drying reddish black; remaining angular or becoming ± terete, bark reddish brown and scaly; with 1-2 pairs of minute cataphylls near the base of the current flush.

Leaves opposite, (sub-)sessile. Petioles 0.5-2 × 1-1.5 mm, absent or very short and stout, drying black. Blades (1.8-) 2.3-4 (-5.2) × (1.2-) 1.5-2.5 (-3.1) cm, ratio 1.3 -2, (broadly) elliptic or (broadly) obovate, base obtuse or rounded, apex rounded, acute, or shortly acuminate, margin revolute; thickly coriaceous (c. 0.3 mm thick), dull, drying dark reddish grey to reddish black above, (very) dusky red beneath; without black gland dots. Midrib impressed above, prominent, rounded, and darker than the lamina beneath. Secondary vein pairs (4-) 5-7, 3-10 mm apart, channelled and inconspicuous above, (slightly) prominent and more reddish than the lamina beneath; intersecondary veins sometimes present. Tertiary veins reticulate, channelled above, indistinct beneath. Inner intramarginal vein 1-2 mm from leaf margin, looping; outer intramarginal vein not present.

Inflorescences terminal, 2-nodate metabotryoids, ≤ 3 cm long, peduncles ≤ 1 cm long, axes angular. Bracts c. 1-1.5 mm long, deltate, keeled, caducous; bracteoles 2 per flower, c. 1 mm long, similar to bracts.

Flowers ≤ 10 per inflorescence, within the inflorescence in triads, anthopodium absent, mature buds 5-6 × 3 mm. Hypanthium 4-5 × 4-5 mm, pyriform, smooth, hypanthium rim 1.5 mm long. Calyx lobes calyptrate with small apical opening, slightly lighter-coloured than hypanthium when dry, splitting irregularly at anthesis, caducous. Petals calyptrate, adhering to the calyx. Stamens c. 50, filaments 6-7 mm long, white, anthers c. 0.4 mm long, ellipsoid. Ovary bilocular, ovules several per locule, ascending. Style 6-7 mm long, pointed.

Fruits and seeds unknown.

Etymology.

The species is named after Pierre Joseph Eyma (1903-1945), one of the early botanists to explore the mountainous regions of Central Sulawesi ( Eyma 1940, van Steenis-Kruseman and van Welzen 2014). Eyma collected many valuable specimens from high-elevation areas, including the type specimen of this species.

Phenology.

The species was collected in flowering state in September 1938.

Distribution and habitat.

S. eymae is endemic to the province of Central Sulawesi and currently only known from the type locality: Mt Lumut on Sulawesi`s eastern peninsula (Figure 4 ). No information on habitat is given on the label of the type specimen. Mt Lumut is made up of ultramafic rocks ( Geological Research and Development Centre 1993) and upper montane (cloud) forest would be the expected vegetation type there at 2200 m.

Conservation status.

With only the type specimen known, we consider S. eymae "Data Deficient" (DD) at present, following the IUCN Red List Categories and Criteria ( IUCN 2012).

Notes.

The species of tribe Syzygieae Wilson (in Wilson et al. 2005, 15) bearing a calyptrate calyx have mostly been treated under the genus Cleistocalyx Blume (1850, 84, see Merrill and Perry 1937). The calyptrate calyx is a relatively rare character, currently known to occur in only about 30 of the> 1200 species of Syzygieae ( Merrill and Perry 1937, Chantaranothai and Parnell 1993, Takeuchi 2002, Biffin et al. 2005, Craven and Biffin 2010). Its occurrence, however, is widely spread over the phylogenetic tree of the tribe; so Cleistocalyx is not monophyletic and has therefore been synonymised under an expanded Syzygium ( Craven et al. 2006, Craven and Biffin 2010).

The flowers of Cleistocalyx are described as having "calyptrate calyces, the undivided, often more or less indurated upper parts of which fall as a lid", the lid often remaining attached at one side of the flower at early anthesis ( Merrill and Perry 1937). In S. eymae , the calyx clearly has the form of a calyptra, but at anthesis it splits irregularly into four or five parts, starting with a minute (<0.5 mm diam.) apical opening (Figure 6 ). One or several of the irregular segments may remain attached to the hypanthium rim shortly after anthesis before eventually being shed. The mode of dehiscence of the calyx thus seems to represent an intermediate condition between Cleistocalyx and classical Syzygium , similar to the situation in Syzygium apodophyllum (F.Muell.) Hyland (1983, 49) from Queensland, Australia.

Most species of Syzygium with calyptrate calyces are clearly different from S. eymae in their much larger leaves with more pairs of secondary veins. The few small-leaved species can all be easily distinguished: S. paradoxum from Borneo differs by the characters given in the diagnosis. S. pseudocalcicola Craven & Biffin (in Craven et al. 2006, 139) from the Philippines and S. canicortex Hyland (1983, 66) from Queensland have many, closely parallel secondary veins and caudate leaf apices, S. apodophyllum has ovate leaves with a long-acuminate apex and clavate flowers.

Syzygium eymae is also superficially similar S. paucivenium (Merr.) Merrill (1951, 408) from Taiwan and the Philippines, but can easily be distinguished from that species by the leaves with channeled, inconspicuous secondary veins on the upper surface (vs. prominent and distinct), smaller inflorescences (<10 vs 20-30 flowers), smaller flowers (mature buds 5-6 vs. 9 mm long), and the presence of the calyptrate calyx (vs. truncate to shallowly lobed).

Several specimens collected on Mt Rorekautimbu in LLNP at 2400 m (e.g. Brambach et al. 0768) may belong here. They are morphologically similar to the type specimen, but have longer petioles. Since we currently lack flowering material of these specimens and because of the large distance between the respective collection localities, we prefer to await more specimens before incorporating these collections in S. eymae .

Figures

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 6. Syzygium eymae: a leafy twig b flower after shedding of calyx and stamens c closed pyriform flower, calyptrate calyx with minute apical opening. All drawings from isotype (L) Eyma 3624.

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.