Micronychia benono Randrian. & Lowry, 2009

Randrianasolo, Armand & Lowry Ii, Porter P., 2009, Four new species and one new combination in the Malagasy endemic genus Micronychia Oliv. (Anacardiaceae), Adansonia (3) 31 (1), pp. 157-168 : 162

2. Micronychia benono Randrian. & Lowry , sp. nov.

( Fig. 3 )

Haec species quoad laminam foliarem utrinque glabram 8-15 cm longam apice plerumque acutam usque acuminatam, in medio nerviis secundariis inter se 12 cm distantibus ad Micronychiam striatam maxime accedit, sed ab ea foliis alternis, petiolo (8-) 10-14 mm longo, infructescentia c. 10 cm longa atque fructu indistincte striato distinguitur.

TYPUS. — Madagascar. Prov. Antsiranana, Ambilobe, Beramanja , Anketrabe , forêt de Kalabenono , sommet rocheux, végétation basse riche en Araliaceae , 13°38’51”S, 48°40’32”E, 818 m, 23.XI.2006, fr., Callmander, Jo Vasaha & Malaza 574 (holo-, MO!; iso-, G!, K!, MO!, P!, TAN!).

PARATYPES. — Madagascar. Prov. Antsiranana, Ambilobe, Beramanja , Anketrabe , forêt de Kalabenono , chaîne de Galoko , 9 km au SE d’Anketrabe, forêt humide de moyenne altitude, sur colline, 13°38’59”S, 48°40’41”E, 785 m, 24.XI. 2006, fr., Razafitsalama & Torze 1129 ( G, K, MO, NY, P, TAN).

DESCRIPTION

Shrub to c. 6 m tall, main stems 6 cm in diam., presumably dioecious; twigs densely lenticellate toward the tips, otherwise glabrous. Leaves alternate, thick chartaceous to subcoriaceous, glabrous on both surfaces, 8.5-15 × 2.6-4.8 cm, elliptic to slightly ovate or obovate, base cuneate to attenuate, apex acute to acuminate, midvein abaxially prominent, secondary venation camptodromous, 12-18 pairs, abaxially prominent, adaxially less prominent, 1.2-1.8 cm from each other in median portion of blade, tertiary veins distinctly evident abaxially, less so adaxially. Petiole 8-14 mm long, glabrous. Flowers not seen. Infructescence a terminal, pendant panicle, c. 10 cm long, glabrous, lenticellate toward the base, primary axis pendant, secondary axes well spaced, borne at nearly 90° angles, distal portions arching upward. Fruits drupaceous, mango-shaped, asymmetric, ovoid to ellipsoid, 1.2-1.6 × 0.6-1 cm, with obscure striations, surface whitish or greenish with a white powdery glaucescence when fresh, dry fruits with evenly-spaced darker lines, often obscured when the membranous exocarp becomes detached.

REMARKS

Micronychia benono is only known from two collections in fruit made in mid-elevation humid forest on sandstone at Kalabenono, which forms part of the Galoko mountain chain in Ambilobe District, SW of Antsiranana ( Fig.2 ). This species has glabrous leaves with an acuminate or acute apex like those of M. striata Randrian. & Lowry , but differs in having alternate leaves, a longer petiole (8-14 vs. 2-6 mm), and an infructescence with well-spaced and almost perpendicular secondary branching.

ETYMOLOGY

The specific epithet refers to the distinctly shaped, isolated Kalabenono massif, where recent botanical exploration has revealed many new species, including the one described here.

CONSERVATION STATUS

With an Extent of Occurrence (EOO) of less than 100 km ², an Area of Occupancy (AOO) no more than 10 km ² and a single known location at an unprotected site, Micronychia benono is assigned a preliminary status of Critically Endangered (CR B1ab(i,ii,iii)+2ab(i,ii,iii)) by application of the IUCN Red List threat criteria ( IUCN 2001).

Figures

FIG. 3. — Micronychia benono Randrian. & Lowry: A, fruiting branch; B, C, details of fruit. Calmander et al. 574. Scale bars: 1 cm.

FIG. 2. — Distribution of Micronychia Oliv.species,mapped on the bioclimatic zones of Madagascar (after Cornet 1974; see Schatz 2000): M. bemangidiensis Randrian.& Lowry (●), M.benono Randrian. & Lowry (), M. kotozafii Randrian. & Lowry (○), M. striata Randrian. & Lowry (◆).