Micronychia Oliv.

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 : 159-162

Genus Micronychia Oliv.

1. Micronychia bemangidiensis

Randrian. & Lowry, sp. nov. ( Fig. 1 )

Haec species quoad petiolum 15-35 mm longum etiam laminam foliarem oblanceolatam basi non decurrentem

subtus secus costam tomentosam ad Micronychiam kotozafii maxime accedit, sed ab ea lamina foliari 3.8-4.7 cm lata basi acuta nerviorum secundariorum in paribus 16 ad 21 distinguitur.

TYPUS. — Madagascar. Prov. Toliara, Iabakoho, Antsotso Avaratra, Ivohibe , low elevation humid forest, 24°34’13”S, 47°12’02”E, 334 m, 21. V.2006, fl., Birkinshaw et al. 1622 (holo-, MO!; iso-, G!, K!, MO!, NY!, P!, TAN!) .

PARATYPES. — Madagascar. Prov. Toliara, Iabakoho, Antsotso Avaratra, Ivohibe , low elevation humid forest, 24°34’13”S, 47°12’02”E, 334 m, 21. V .2006, fl., Birkinshaw et al. 1634 (G, K, MO, NY, P, TAN) .

DESCRIPTION

Small tree 3-4 m tall, dioecious; twigs densely rusty-brown sericeous-tomentose toward the tips. Leaves alternate, sometimes subopposite, chartaceous, adaxially glabrous, abaxially sparsely tomentose along midvein, 11.4-22.7 × 3.8-4.7 cm, oblanceolate, base acute, apex usually acuminate, sometimes rounded, midvein abaxially prominent, secondary venation camptodromous, 16 to 21 pairs, abaxially prominent, less prominent adaxially, 1.1-2.1 cm from each other in median portion of blade, tertiary veins distinctly visible abaxially. Petiole 15-35 mm long, densely rustybrown sericeous-tomentose. Inflorescence a terminal, pendent panicle, 8.5-21.5 cm long, densely deep golden brown to rusty-brown sericeoustomentose. Staminate flowers large, 5-7 mm long; pedicel 5 mm long; sepals 2.1 × 2 mm, ovate, imbricate, adaxial surface glabrous, abaxial surface sericeous; petals 6 × 2.2 mm, ovate, imbricate, adaxially glabrous, abaxially sericeous; stamens 5, filaments 3 mm long, S-shaped, glabrous, anthers 2.2 × 2 mm, ovate with a few sericeous trichomes; disk glabrous, slightly cup-shaped, 2 mm in diam.; ovary reduced. Pistillate flower and fruit not seen.

REMARKS

Micronychia bemangidiensis is only known from two collections with staminate flowers, both from low elevation humid forest on the eastern slope of Ivohibe peak c. 55 km N of Fort Dauphin, in extreme SE Madagascar ( Fig. 2 ). This species can be easily distinguished from other members of the genus by the combination of its narrow and long oblanceolate leaf blade with an acute base and long petiole. It resembles M. kotozafii Randrian. & Lowry in having petioles that exceed 15 mm in length, but differs in having narrower leaf blades (3.8-4.7 vs. 4.7-9.3 cm) with fewer pairs of secondary veins (16 to 21 vs. 20 to 24 pairs) and an acute (vs. cuneate) base.

45°E 50°

15°S

20°

25°

ETYMOLOGY The species name refers to the Bemangidy forest, located in the central part of the Tsitongambarika range, the easternmost mountain chain in southern Madagascar.Bemangidy appears to be of exceptional conservation importance, as it is one of the last remaining areas of well-preserved low elevation humid forest in the region, extending down to below 100 m above sea level. Recent botanical inventory work has yielded material of several new species, including Gnidia razakamalalana Z.S.Rogers (Thymelaeaceae) ( Rogers 2006) and seven as-yet unpublished species of Araliaceae (Lowry unpubl. data).

VERNACULAR NAME

Rehika.

CONSERVATION STATUS

With an Extent of Occurrence (EOO) of less than 100 km ², an Area of Occupancy (AOO) of no more than 10 km ², and a single known location situated outside Madagascar’s protected areas system, Micronychia bemangidiensis is assigned a preliminary status of Critically Endangered (CR B1ab(i,ii,iii)+2ab(i,ii,iii)) using the IUCN Red List threat criteria ( IUCN 2001).

Figures

FIG. 1. — Micronychia bemangidiensis Randrian.& Lowry:A, flowering branch;B, unopened flower;C, longitudinal section of unopened male flower; D, tip of male inflorescence. Birkinshaw et al. 1622. Scale bars: A, 2 cm; A’, 6.5 mm; B, C, 2 mm; D, 4 mm.

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 (◆).