Syzygium aromaticum ( Linnaeus 1753: 515 ) Merrill & L.M.Perry (1939: 196)

Byng, James W., Barthelat, Fabien, Snow, Neil & Bernardini, Benedetta, 2016, Revision of Eugenia and Syzygium (Myrtaceae) from the Comoros archipelago, Phytotaxa 252 (3), pp. 163-184 : 175-177

1. Syzygium aromaticum ( Linnaeus 1753: 515) Merrill & L.M.Perry (1939: 196)

For synonyms see WCSP (2015).

Trees to 21 m. Branchlets terete, ca. 2 mm diameter, whitish. Petioles 1.5–3 cm. Leaves smelling of cloves when crushed. Blades 8–12 × 3.5–5 cm, elliptic, lanceolate or obovate; base attenuate, apex acute to acuminate; secondary vein pairs 20–30; intramarginal vein ca. 1–1.5 mm from margin. Inflorescences terminal, up to 15-flowered. Flowers ca. 1.8 cm in diameter at anthesis, pseudostalk ca. 8 mm long. Hypanthium 11–12 × 3 mm, clavate, pinkish to crimson. Calyx lobes 3.5–4 × 3–3.5 mm, ovate. Petals 7–8.5 × 7–8 mm, free, orbicular. Stamens 7–7.5 mm long, yellowish. Style ca. 4 mm long. Fruits 2–3 cm long, oblong-ellipsoid, dark purple, reddish or black at maturity.

Vernacular name:— Giroflier (French).

Specimens examined:— UNION OF THE COMOROS. Anjouan: Bernan , November 1903 (fl.), s.n. (P!) ; 1904 (fl.), Humblot s.n. (P!). Grande Comore: N’tsouéni, 22 August 2006 (fl.), Ali Mohamed Kaou s.n. (P!) ; 7 October 1975 (with buds), Coulon 127 (P!). MAYOTTE [ FRANCE]: Pistes Grands bambous, Combani–Bouyouni (fl.), C. Mas 316 (P!) .

Notes:— Widely cultivated throughout the archipelago as the source of cloves, particularly on Anjouan.

2. Syzygium comorense Byng & N. Snow , sp. nov. Type : — MAYOTTE [ FRANCE]. Sohoa, 20 August 1996 (fl.), O. Pascal 634 (holotype P! [barcode P00144743]; isotypes B, K!, MO, NY, WAG!). Figure 7

A species with angular branchlets and slender petioles (5–15 mm); leaves elliptic, oblong or oblanceolate with many prominent tertiary veins; apices acute to acuminate. In the Comoros the species could be confused with S. labatii but it differs by its longer petioles, more open inflorescences and smaller flowers (<12 mm).

Trees or shrubs, to 25 m; bark grey or light brown. Branchlets terete or subangular, drying grey to reddish brown. Petioles ca. 5‒15 × 0.7‒1 mm, slender. Leaves coriaceous; drying olive green to brownish bronze above, paler below, dull on both sides. Blades 4.5‒9.5 × 1.9‒5.2 cm, elliptic, oblong or oblanceolate, base cuneate, apex acute or acuminate, up to 1 cm long; margin flat; secondary vein pairs 14‒20, 1‒3 mm apart, more or less prominent on both sides, angle of divergence from mid vein 65–70°; tertiary veins many, more or less prominent, difficult to distinguish from secondary veins; inner intramarginal vein 1‒3 mm from leaf margin, outer intramarginal vein ca. 0.5 mm from leaf margin. Bracts and bracteoles ca. 1 mm long, oblong, caducous. Inflorescences terminal or sometimes in subterminal axils, 3‒5.5 cm long, often laxly branched, axes terete to subangular, flowers up to 80, in clusters of 3‒5. Flowers ca. 5‒10 mm in diameter at anthesis, buds ca. 3 mm in diameter, pseudostalk ca. 2 mm long. Hypanthium 3‒6 × 3‒6 mm, infundibuliform, conspicuously pinkish-red at the apex. Calyx lobes 1‒3 × 3‒4 mm, broadly triangular to round. Petals ca. 3 × 3 mm, calyptrate, orbicular. Stamens 5‒8 mm long, white or whitish-yellow; anthers 0.3‒0.5 mm long. Style 4‒6 mm long. Fruits ca. 1.2 × 1‒2 cm, globose, dark purple to violet at maturity, hypanthium rim 3‒4 mm in diameter.

Distribution:— Endemic to the Comoros archipelago ( Union of the Comoros, Mayotte [ France]).

Habitat and ecology:— Low hill forests to montane forests and ridges; 200‒1500 m elev.

Vernacular names:— Soua ravou lahi and Souaravou lahy (dialect Shibushi), M’rimeou (dialect Mohelien).

Paratypes:— MAYOTTE [ FRANCE]. Sohoa , 12 December 1996 (with flowers and fruits), O. Pascal 790 (K!, MO, P!, WAG) ; 25 August 2005 (fl.), F. Barthelat 1503 (G, K!, MAYOTTE, MO, P!) ; 14 November 2011, J.W. Byng 112 (K!, P!). Bépilipili, 30 July 1996, O. Pascal 609 (B, G, K!, MO, NY, P!, WAG). UNION OF THE COMOROS. Anjouan: southern ridge of Mont Tringi , 16 November 2011, J.W. Byng 114 (K!, P!) ; & 115 (K!, P!); & 116 (K!, P!). Grande Comore: Versant est du Karthala, November 2009 (fl.), M. Charahabil 37 (HKM, P!). Mohéli: Miringoni, forêt St. Antoine , 20 March 1957 (fr.), Service Forestier (Capuron) 16746-SF (P!) .

Conservation status:— During fieldwork in 2011 the species was rarely encountered on Mayotte, with only one large individual seen at Sohoa, whilst on the southern ridges of Mont Tringi on Anjouan it was relatively frequent but only at higher elevations. The species is generally restricted in distribution and occurs in some of the remaining forests of the islands that are increasingly susceptible to slash and burn agriculture and invasion by alien species, such as Cinnamomum camphora (Linnaeus) J.Presl ( Linnaeus 1753: 369; Berchtold & Presl 1825: 36). The species is known from five subpopulations with an AOO of less than 20 km 2 and should be considered Endangered (EN B2ab(iii)) according to the IUCN Red List Criteria ( IUCN 2014).

Notes:— This is the most widespread species of Syzygium in the archipelago and was previously determined as S. guineense ( Pascal 2002, Barthelat & Boullet 2005). The results from sequencing samples from both Mayotte and Anjouan (Byng unpublished data) indicate that they form a well-supported clade but are unrelated to continental S. guineense , and thus should be described as a new species. Morphologically the Comoros species is difficult to separate from the continental S. guineense because both share numerous characters, notably the long slender petioles, often acute to acuminate leaf apices, numerous fine tertiary veins, and small whitish flowers. However, images of the flowering Comoros species by the second author ( Figure 8 ) show a conspicuously pinkish-red hypanthium which cannot be seen in dried material of S. comorense , and reddish hypanthia are rarely present in continental species of Syzygium .

Figures

FIGURE 7. Syzygium comorense Byng & N. Snow. A bark; B petioles; C angular branchlet; D inflorescences; E upper leaf surface; F immature and mature fruits; G lower leaf surface. (A–C, E, G Byng 112; D Barthelat 1503; F Pascal 790). (F MNHN). Scale bar = 5 mm (B–C) or 2 cm (D–G).

FIGURE 8. Holotype of Syzygium humblotii (H. Perrier) Labat & Schatz. Humblot 1329. Scale bar = 2 cm.