Eugenia vanwykiana N. Snow, 2012

Snow, Neil, Rabenantoandro, Johny, Randriatafika, Faly, Rabehevitra, David, Razafimamonjy, N. Darie & Cable, Stuart, 2012, Studies of Malagasy Eugenia (Myrtaceae) - III: Seven new species of high conservation concern from the eastern littoral forests, Phytotaxa 48 (1), pp. 39-60 : 56-58

Eugenia vanwykiana N. Snow sp. nov. ( Figs. 1 , 9 ).

A congeneribis madagascariensibus combinatione characterum sequentium distinguitur: arbor mediocris; ramuli juniores et hypanthium dense tomentosum, pilis dibrachiatis aliquantum ferrugineis; ramuli complanati vel teretes; folia obovata vel elliptica, (20–)30–47 x (10–) 15–39 mm, nervo medio supra sulcato; hypanthium valde costata.

Type: ― MADAGASCAR. Prov. Antsiranana: Vohémar, Nosibe, Anjiabe. Village le plus proche: Anaborana près du lac Sahaka , 13°04’43’’S, 49°54’04’’E, 10 m, 23 Février 2003, J. Rabenantoandro 1319, R. Rabevohitra, R. Razakamalala & S. Mathieu (holotype MO! [sheet no. 6038327]; isotypes BISH! [sheet no. 731731], P, TAN) .

Trees 10–12 meters; bark unknown. Indumentum on young branchlets and hypanthium dense (trichomes dibrachiate and somewhat ferrugineous). Branchlets laterally compressed becoming rounded, brownish-gray, becoming slightly scaly or fissured, densely sericeous; internodes 1.2–3.0 cm long. Leaves coriaceous, evenly distributed along branchlets, discolorous (fresh color unknown), matte above and below; venation brochidodromous. Stipules absent. Petioles 4.2–10.5 mm long, deeply sulcate above, densely hairy, becoming glabrous and somewhat rugose-wrinkled. Leaf blades (2.0–)3.0–5.5 x (1.0–) 1.5–3.9 cm, narrowly elliptic or elliptic to narrowly obovate or obovate, base cuneate, margin flat to slightly revolute, laminar surface flat to mildly wavy, apex obtuse, tip acute (or less frequently acute); adaxial surface sparsely hairy along midvein and proximally but becoming glabrous, oil glands faint or not visible, midvein sulcate proximally becoming flush distally; abaxial surface sparsely hairy becoming glabrous, oil glands relatively occasional to common, flush, faint and of uniform size, midvein protruding and striate but becoming flush distally, secondary veins relatively few and not particularly distinct, the distal ends of secondary veins connected by a somewhat arching intramarginal vein less than 1.5–5.5 mm from laminar margin at midpoint. Inflorescence axillary or terminal, in fascicles of monads, triads (3-flowered cymes) or few-flowered panicles. Peduncles 2–15 mm long, terete to laterally compressed, stiff. Pedicels 3–4 mm long, densely hairy, anthopodia and metaxyphylls absent. Bracteoles 0.7–1.3 x <0.5 mm, narrowly triangular to broadly ovate or oblate, scale-like, mostly densely hairy. Hypanthium 3–4 mm long, 4–5 mm wide at base of calyx lobes, obconic, prominently ribbed in flower, densely hairy, oil glands (if present) completely obscured by hairs. Calyx lobes 4, 3– 4 mm long, ovate to broadly ovate, hairy below especially near margins and center, yellowish. Petals 4, 7.5–9.5 x 7–8 mm, broadly obovate to very broadly obovate, glabrous, yellowish, oil glands absent or sparse. Staminal ring densely hairy, 3.0– 3.2 mm wide. Stamens ca. 75–100; filaments 6–10 mm; anther sacs 0.8–1.0 mm long, globose to subcylindrical, dorsifixed, eglandular. Style 10.5–11.5 mm, glabrous, sparsely glandular; stigma terete and scarcely if at all capitate. Locules 2; placentation axile; ovules 15–17 per placenta, apically (i.e., opposite point of attachment) broad with well-defined angular sides but narrowing towards base, radiating from centrally positioned, rounded placenta. Fruit evidently green (not confirmed).

Field characters:— Tree to 12 m tall; leaves elliptic to obovate, upper midvein impressed above in lower half of blade; hypanthium conspicuously ribbed in flower and densely hairy; calyx green, petals yellow, fruits green.

Distribution:— Eugenia vanwykiana is known from two collections from the Analabe littoral forest near Lac Sahaka, located east of Anaborano and about 2.8 km west of the coastline ( Fig. 1 ). This general area is approximately 33 km northwest of Vohémar and about equidistant from the coastal outlets of the Manambato and Manankolana rivers.

Habitat and ecology:— In littoral forest over sand.

Phenology:— Flowering February through May. Fruiting indicated from both known gatherings (February and May) but none seen by the first author.

Additional specimen examined (paratypes):— MADAGASCAR: Antsiranana: Fivondronana: Vohémar, Firaisana : Nosy Be (Nossi-be), Fokontany : Anjiabe , 13°04’43’’S, 49°54’04’’E, 13 May 2004, R. Razakamalala 1324 et al. (BISH! [sheet nos. 731742, 731743], MO!, P, TEF) .

Eponomy:— The specific epithet honors Dr. Abraham van Wyk (1952–) of the University of Pretoria, Gauteng Province, South Africa, whose studies provided important insights into the the anatomical and morphological variability of the South African species of Eugenia .

Conservation status:— Recent satellite imagery suggests that the Analabe littoral forest near Lac Sahaka remains relatively undisturbed and relatively free of roads. However, Consiglio et al. (2006) estimated only ca. 2200 hectares of remaining littoral forests in this region. Unlike the other species proposed herewith, recent field observations are unavailable for Eugenia vanwykiana and no attempt was made to estimate its population size at Analabe.With just two collections, an AOO of 9 km 2, and a single subpopulation constituting a single location not encompassed within a protected area, E. vanwykiana is assigned a preliminary status of “Endangered” (EN: B2ab(i, iii)) because of the relatively undisturbed area where the species is growing.

Discussion:— The label on the type specimen indicates the fruits are greenish but we have seen no fruits on herbarium material, and green typically applies only to immature fruits in Eugenia .

Figures

FIGURE 1. Madagascar. A: Location of Eugenia vanwykiana (․) in the northeast. B. The southeast region of Madagascar in vicinity of Tolagnaro (detailed in Fig. 2). Currently forested areas are shaded in gray.

FIGURE 9. Isotype of Eugenia vanwykiana (Rabenantoandro 1319 et al. [BISH]).