Eugenia delicatissima N. Snow, Callm. & Phillipson, 2015

Snow, Neil, Callmander, Martin & Phillipson, Peter B., 2015, Studies of Malagasy Eugenia - IV: Seventeen new endemic species, a new combination, and three lectotypifications; with comments on distribution, ecological and evolutionary patterns, PhytoKeys 49, pp. 59-121 : 65

Eugenia delicatissima N. Snow, Callm. & Phillipson sp. nov. holotype (Figure 8): http://www.tropicos.org/Image/100314909

Haec species a congeneris madagascariensibus lamina foliari tenuiter coriacea irregulariter sinuosa atque pedicello gracili delicato distinguitur.

Type.

MADAGASCAR. Prov. Mahajanga: Tsaratanana massif, N of Mangindrano, along trail from camp at Mahatsabory to Be Pia, 14°07'40"S, 48°58'50"E, 2350 m, 20 Oct. 2001, P.P. Lowry II 5438 + R. Razakamalala & R. Lala (holotype: MO-6224858!; isotypes:P [P05208430]!, TAN).

Description.

Shrubs to treelets 2-4 m tall; bark of main bole smooth, light brownish or grayish. Plants glabrous or (where noted) sericeous (hairs dibrachiate, reddish). Branchlets laterally compressed, sparsely hairy upon emergence but becoming glabrous, oil glands faint, sparse or occasional and of uniform size, flush or only slightly protruding, smooth, light brown or gray. Leaves evenly distributed along branchlets, thinly coriaceous, venation brochidodromous, strongly discolorous, matte above and below. Axillary colleters if present then soon deciduous. Petioles 4.0-6.5 mm long, slightly to deeply sulcate above, sparsely glabrescent, eglandular. Leaf blades (18-)30-52 mm × (8-)18-25 mm, narrowly elliptic to elliptic (or occasionally broadly elliptic), base cuneate to strongly cuneate, margin flat to slightly revolute (dry), surface slightly irregularly wavy (sometimes including along midvein), apex acute to acuminate, tip obtuse to mostly acute or acuminate or slightly falcate; adaxial surface glabrous, oil glands faint, dense and of uniform size, midvein sulcate but becoming flush distally; abaxial surface glabrous, oil glands faint, sparse to occasional and of different sizes, vein connecting tips of secondaries near margin slightly arching arching only slightly, 0.5-0.9 mm from margin at midpoint of leaf blade. Inflorescence terminal, axillary or ramiflorous, consisting of short brachyblasts with 1-3 pairs of monads, often 2 or more brachyblasts per axil or point of insertion (on naked branches), or monads arising in axils. Pedicels 3-11 mm long, 0.3-0.4 mm thick, stiff to somewhat flexuous, ascending to sometimes reflexed, glabrous or very sparsely short-hairy, lightly striate, round, oil glands sparse and faint, anthopodia and metaxyphylls absent. Bracteoles 0.8-1.3 mm long, less than 0.5 broad (at base), very narrowly triangular to ovate, normally persisting in anthesis, sparsely hairy (or merely ciliate). Hypanthium obconic, (0.8-)1.2-1.3 mm long, 0.9-1.0 mm broad at apex beneath base of calyx lobes, sparsely hairy to glabrous, smooth, oil glands sparse to common and protruding. Calyx lobes 4, 1.3-1.9 mm long, broadly ovate to rounded, sparsely ciliate, sparsely glandular, greenish. Petals 4, 2.8-4.4 × 1.6-1.8 mm, obovate to broadly elliptic, glabrous or sparsely ciliate apically, white, oil glands sparse to common, of uniform size and somewhat protruding below. Staminal disk ca. 1.8 mm in diameter, sparsely hairy. Stamens 15-25; filaments 3-4 mm long; anther sacs ca. 0.5 mm long, globose to subcylindrical, dorsifixed, brown, connective with an apical gland. Style 4-5 mm long, glabrous; stigma narrow. Fruit 0.9-1.4 × 0.8-1.6 cm, subglobose to globose, texture smooth, rounded or tapered at base, glabrous, greenish but drying blackish, calyx lobes reflexed flat against apex.

Etymology.

A superlative of delicata in Latin, in reference to the thin, almost thread-like pedicels.

Vernancular name.

Rotramadinika (Rakoto 294).

Phenology.

Flowering in late October through at least early November; fruiting November.

Distribution.

Known from the northern mountains of Madagascar in and around the Manongarivo and Tsaratanana protected areas and in the Sorata region (Fig. 4).

Habitat and ecology.

High elevation montane forests with bamboo; 1100-2350 m.

Conservation status.

With an EOO of 3278 km2, an AOO of 36 km2 and four subpopulations, two of which are situated within the protected area network (Manongarivo, Tsaratanana), Eugenia delicatissima is assigned a preliminary risk of extinction of “Vulnerable” [VU B1ab(iii)+2ab(iii)] following the IUCN Red List Categories and Criteria ( IUCN 2012). At the summit of Beampoko Eugenia delicatissima was indicated as being rare (Rakotovao 2565).

Comments.

Eugenia delicatissima is part of an apparent species group characterized by thinly coriaceous, sinuous leaf blades and slender, often elongate and delicate pedicels.

The thinly coriaceous, sinuous leaf blades of Eugenia delicatissima are somewhat suggestive of Eugenia echinulata , but the fruits of Eugenia delicatissima are smooth (e.g. Randriambololomamonjy 270), unlike the highly irregular (warty to echinate) texture of of Eugenia echinulata .

The slender pedicels are similar to those of Eugenia tropophylla H. Perrier, a highly heterogenous species that Perrier de la Bâthie (1953a: 167) initially described with three subspecies, none of which match Eugenia delicatissima . The taxonomy of Eugenia tropophylla needs serious revision and will be the subject of a forthcoming publication.

An indetermined specimen of Eugenia from Mayotte in the Comoros (Barthelat 992 [G, K, MO]) also has slender pedicles, but they are much shorter than those of Eugenia delicatissima . The leaf blades of the Barthelat specimen are longer and the bases rounded, unlike the cuneate bases of Eugenia delicatissima . Taxa from eastern and southern Africa with delicate pedicels include Eugenia capensis (Eckl. & Zeyh.) Sonder subsp. gracilipes F. White (e.g., P. van Wyk BSA 2844 [MO] from Zimbabwe and J.D. Chapman 6570 [MO] from Malawi). Another species from Africa with delicate pedicels that differs from Eugenia delicatissima in various traits is Eugenia congolensis De Willd & T. Durand (e.g., J. Madidi 642 et al. [MO] and F. Bujo 602 [MO] from Congo). None of these, however, are good morphological matches for Eugenia delicatissima .

Specimens examined.

MADAGASCAR. Prov. Antsiranana: Massif du Manongarivo, [13°59'24"S, 48°22'12"E], c. 1600 m, 1909, Perrier de la Bâthie 6503 (P [P05258587]); Sommet de Beampoko, Ambohimirahavavy, 14°13'55"S, 49°08'23"E, 2137 m, 21 Nov. 2005, C. Rakotovao 2565 (G, MO-6174672); Vohemar, Andrafainkona, Ampsarahina, forêt de Maromaniry située à 5 km au N d’Ampiarahina, 13°38'49"S, 49°32'13"E, 1177 m, 7 Nov. 2007, O. Randriambololomamonjy 270 + R. Razakamalala & Jaowind (MO-6186659); Massif du Tsaratanana, crête (et ses abords) séparant les bassins du Sambirano et de la Mahavavy, entre l’Andohanisamborano et la cote 2362, 9-10 Nov. 1966, Service Forestier 27019 (P [P05097488]).