Eugenia wilsoniana N. Snow, 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 : 85-88

Eugenia wilsoniana N. Snow sp. nov. holotype (Figure 21): http://www.tropicos.org/Image/100314905

Haec species Eugeniae bemangidiensi N. Snow simillima, sed ab ea inflorescentia axillari longipedicellata distinguitur; etiam ad altitudines superiores crescit.

Type.

MADAGASCAR. Prov. Toamasina: Alaotra Mangoro Reg., Moramanga, Ambohibary, Ampitambe, 18°48'55"S, 48°16'37"E, 1103 m, 14 Oct. 2008, R. Rakotondrajaona 649 (holotype: MO-6419537!); isotypes: P, TAN).

Description.

Shrubs or trees, (1-)2-6 m. Trunk dbh ca. 2 cm (measurements few); bark of main bole fissured, maroon. Indumentum where present of highly asymmetric and short, ferrugineous, dibrachate hairs. Branchlets laterally compressed, smooth, sparsely puberulous, drying light brown to greenish, punctate glands absent. Leaves opposite or disjunct opposite, mostly concentrated near tips of branches; venation reticulate; blades thinly coriaceous, dark green above and lighter green below. Axillary colleters obscure when present. Petioles 3-5 mm, deeply and narrowly sulcate adaxially, laterally compressed, elgandular, glabrescent (especially abaxially), longitudinally striate initially but thickening and becoming somewhat latitudinally striate with age. Leaf blades 4.0-12.5 × 1.4-3.0 cm, narrowly elliptic to narrowly ovate, base rounded and slightly constricted-conduplicate above petiole, apex acute, margins flat; adaxial surface glabrous, eglandular, midvein narrowly but deeply sulcate lower 2/3-4/5; abaxial surface like adaxial except: midvein protruding, sometimes prominently glandular and longitudinally striate, secondary veins faint to prominent, arising only 10-20° from midvein, tertiary veins faint to nearly as prominent as secondaries; intramarginal vein 1.0-1.5 mm from leaf edge at midpoint of blade. Inflorescence terminal, axillary, or arising on naked branch of current year’s growth. Flowers solitary, or occasionally as up to four arising from short brachyblasts; pedicels 6-12 × ca. 0.5 mm, glabrous, strongly laterally compressed (especially distally), longitudinally striate, sparsely to moderately glandular. Bracteoles 2, 0.6-1.1 mm, narrowly ovate to ovate, sparsely hairy abaxially and apically, rigid, somewhat ascending to appressed against base of hypanthium. Hypanthium 2.5-4.0 mm, cupuliform, sparsely hairy becoming glabrous, sparsely to moderately (but only faintly) glandular. Calyx lobes 4, 4-5 × 3-5 mm, oblate to broadly elliptic, apex broadly obtuse to rounded, minutely and sparsely ciliate in upper half, prominently glandular, greenish when fresh. Petals 4, 4-5 × 2-3 mm, widely elliptic to ovate, sparsely short-ciliate upper 1/2-1/3, faintly and somewhat sparsely glandular, whitish or pinkish. Stamens exserted, staminal disk ca. 4 mm diameter, more or less square from above, short-hairy, adjacent ovary apex glabrous; filaments 2-3 mm; anthers 0.8-1.0 mm, elliptic, yellow, sub-basifixed, apical gland between connectives lacking. Styles 7-8 mm, glabrous; stigma narrow and scarcely if at all capitate. Berries (immature?) 12-15 × 12-15 mm, globular, greenish.

Etymology.

In honor of Dr. Peter G. Wilson (b. 1950) of the Royal Botanic Gardens in Sydney, Australia; colleague, collaborator, and long-time student of Myrtaceae (e.g., Wilson and Waterhouse 1982; Wilson et al. 2005; Snow and Wilson 2010; Wilson 2011).

Vernacular name.

Hazompasina (Antilahimena 4935); Rotra (Ravelonarivo 3148).

Phenology.

Flowering mid-October through mid-November; fruiting October and November.

Distribution.

East-central Madagascar in Toamasina Province, occurring near Analamazaotra National Park (Fig. 2).

Habitat and ecology.

In humid, sometimes disturbed forests at middle altitudes from ca. 980-1103 m.

Conservation status.

With five collections known, an AOO of 9 km2 and one subpopulation that is situated outside the protected area, Eugenia wilsoniana is assigned a preliminary risk of extinction of "Critically Endangered" [CR A3c+B1ab(iii)] following the IUCN Red List Categories and Criteria ( IUCN 2012). Current data suggest the species has a narrow distribution, and the montane evergreen tropical forests where the species grows are threatened by mining activities. The discovery of this species in one of the nearby protected areas probably would allow downlisting to “Endangered”.

Comments.

The leaf and floral morphologies of Eugenia wilsoniana are suggestive of Eugenia diospyroides H. Perrier. However, Eugenia wilsoniana has much shorter leaves and a hairy staminal ring, in contrast with the much larger leaves and glabrous staminal ring of Eugenia diospyroides (e.g., Randriatifika 118 et al. [KSP]). This new species resembles even more closely another newly described species herein, Eugenia bemangidiensis , which differs by its cauliforous inflorences occurring in tight, relatively short fascicles, secondary veins on the leaf blades arising at steeper angles, and occurring in a different habitat at much lower elevations some 750 km southeast from the presently known occurrences of Eugenia wilsoniana . Moreover, the foliage and floral parts of Eugenia bemangidiensis are entirely glabrous, the abaxial laminar midvein protrudes less prominently, the adaxial laminar sulcus is not as deep or narrow, and its adaxial petiolar sulcus is broader and shallower than those of Eugenia wilsoniana .

Specimens examined.

MADAGASCAR. Prov. Toamasina: Ambatovy, Sahaevo forest, 18°50'26"S, 48°16'33"E, 11 Nov. 2006, P. Antilahimena 4935 & F. Edmond (MO-6338238); ibid. loc., 18°50'26"S, 48°16'34"E, 23 Nov. 2008, P. Antilahimena 6912 + B.A. Ratodimanana, D. Ravelonarivo, E. Félix & M. Ratvomanana (MO-6447030); Ambatovy, Antaniditra, 18°49'11"S, 48°16'53"E, 13 Oct. 2008, R. Bernard 1154 (MO); Ampitambe, Ambatovy, 18°49'06"S, 48°17'06"E, 1041 m, 13 Oct. 2008, R. Rakotondrajaona 642 + M. Ratolojanahary (MO-6419531); Mararano, Marovoay, 18°48'10"S, 48°17'59"E, 14 Nov. 2008, D. Ravelonarivo 3148 (MO-6447573).