Micronychia acuminata Randrianasolo, 2000

Randrianasolo, Armand, 2000, A taxonomic revision of the Malagasy endemic genus Micronychia (Anacardiaceae), Adansonia (3) 22 (1), pp. 145-155 : 147-148

Micronychia acuminata Randrianasolo , sp. nov.

Haec species a congeneris foliis oblanceolatis ad anguste ellipticus parvis (2.8-6.5 cm longis, 1-2 cm latis) atque apice acuminato logissimus 1-1.5 cm) differt.

TYPUS. — SF 18114 (Capuron), Madagascar, Toamasina Prov.: RNI n° 1 Betampona, Ambodiriana , 250-500 m, 22 Aug. 1957, fr. (holo-, P!; iso-, P!, TEF) .

Trees or treelets; young twigs glabrous, with lenticels. Leaves subcoriaceous, persistent; blades oblanceolate to narrowly elliptic, 2.8-6.5 cm long, 1-2 cm wide, apex acuminate (acumen 1- 1.5 cm long), base acute, decurrent, margin entire; adaxial and abaxial surfaces glabrous; venation pinnate and mixed craspedodromous, midvein prominent below, 10-12 pairs of secondary veins, 2-8 mm apart, more or less parallel to arcuate, slightly prominent below, forming an obtuse angle with the midrib at leaf base, tertiary veins ramified and admedial. Petiole 3-4 mm long, shallowly channeled, glabrous. Male and female flowers unknown. Infrutescence terminal, ca. 2.5 cm long, branches regular, glabrous. Fruit 1-1.4 cm long, 0.9-1.2 cm broad, asymmetrical, mango-shaped, with longitudinal striations, glabrous, mesocarp resinous, endocarp thin. — Fig. 1 .

From observation of the available specimens, and despite the fact that the flowers are unknown, this species is strikingly different from the other members of Micronychia by its very long acuminate leaf apex ( Fig. 1 ). Dr. George SCHATZ (MO) has collected a unicate specimen (Schatz 1842) in North East Madagascar that seems to have a leaf pattern similar to that of M. acuminata but lacks a decurrent leaf base. However, with only one sheet available, it is difficult to assign SCHATZ’ s collection to M. acuminata with certainty, and more material will be needed to establish its taxonomic status.

HABITAT, DISTRIBUTION AND PHENOLOGY. — Micronychia acuminata has so far been collected only in the Betampona reserve, an area with humid eastern forest on laterite, between 250- 500 m elevation ( Fig. 2 ). The fruiting period is in August and September, and flowering probably occurs in April and May.

VERNACULAR NAMES. — Tsiramiramy, Hazondomohina.

PARATYPES. — MADAGASCAR: RN 2649 (Georges Rakotonirina), Toamasina Prov., Ambodiriana, RNI n° 1 Betampona, 26 Aug. 1950, fr. (P!); RN 4398, 7 Sep. 1952, fr. (P!); RN 5361, 28 Aug. 1958, fr. (P!); RN 9743 (Razanaparany), Ambodiriana , RNI n° 1 Betampona , 24 June 1953, fr. (P!) .

Figures

Fig. 1. — Micronychia acuminata: A, branch with leaves and fruits; B, shape of mature fruit; C, cross section of fruit; D, leaf with nervation.

Fig. 2. — Geographic distribution of Micronychia acuminata, M. danguyana, and M. macrophylla.