Abrahamia sambiranensis Randrian. & Lowry, 2017

Randrianasolo, Armand, Lowry II, Porter P. & Schatz, George E., 2017, Taxonomic treatment of Abrahamia Randrian. & Lowry, a new genus of Anacardiaceae from Madagascar, Boissiera 71, pp. 1-152 : 119-120

29. Abrahamia sambiranensis Randrian. & Lowry , spec. nova ( Fig. 26 ).

Typus: MADAGASCAR. Prov. Mahajanga: Rég. Diana , Ambato forêt classée, c. 40 km N d’Ambanja, 13°26’S 48°33’E, 90-459 m, 23.XI.1996, fr., Randrianaivo et al. 29 (holo-: MO- 6671436 !; iso-: G!, MO- 6671435 !, P [ P06775160 ]!, TAN [ TAN001998 ]!).

Diagnosis

Abrahamia sambiranensis Randrian. & Lowry can be distinguished from other members of the genus by the combination of large (10-19 3 2.5-5.6 cm), coriaceous leaves with numerous (50- 60) distinctly raised secondary veins and a folded apex in dry material, its long petiole (30-65 mm), and its large, glabrous fruits (2.5-3 cm long).

Description

Trees 10-15 m tall, 15-18 cm DBH, bark with white latex; young twigs pubescent towards the tips. Leaves alternate, clustered toward the branch ends; blade oblanceolate or narrowly elliptic to lanceolate, 10-19.4 3 3.2-5.5 cm, coriaceous, apex acuminate, folded in dry material, margin undulate, base cuneate to broadly cuneate, adaxial surface glabrous, often glaucous, abaxial surface sparsely sericeous, more so on midvein, venation craspedodromous, midvein prominent abaxially, secondary veins 50-60 pairs, more or less parallel, 2-4 mm apart, raised on both surfaces, tertiary veins not visible on both surfaces; petiole (20)- 25-58 mm long, 2-3.5 mm in diam., canaliculate on adaxial surface, tomentose. Inflorescence axillary, a panicle, 2-9.5 cm long, very few flowers reaching maturity, axes pubescent. Male flowers 5-merous; pedicel c. 0.5-1 mm long, pubescent; calyx lobes triangular to ovate, 1 3 1 mm, connate at base, adaxial surface glabrous, abaxial surface pubescent; corolla lobes ovate, 2.5 3 1.5 mm, imbricate, adaxial surface glabrous, abaxial surface pubescent; stamens 5, filaments 1 mm long, anthers c. 1 3 1 mm, obloid to ovoid; disk cupuliform, glabrous; rudimentary ovary absent. Female flowers unknown. Fruits 2.5-3 3 1.5-1.8 cm, ellipsoid, pubescent when young, glabrescent, with fine longitudinal striations.

Distribution, ecology and phenology

Abrahamia sambiranensis is restricted to humid forests in the Sambirano region of NW Madagascar and extends into the northern part of the island ( Map 9 ). It flowers in July and August, and fruits have been collected in October and November.

Conservation status

With an EOO of 1,717 km 2, a minimum AOO of 28 km 2, and seven localities, with only a single subpopulation within a protected area (Galoko), A. sambiranensis exists at 7 locations, six of which are subjected to pressure from forest exploitation and land clearing; it is therefore assigned a preliminary conservation status of “Vulnerable” [VU B1ab(iii)+2ab(iii)] using the IUCN Red List Categories and Criteria ( IUCN, 2012).

Notes

Abrahamia sambiranensis vegetatively resembles A. elongata , but differs by having leaves that lack tertiary venation (vs present and raised on both surfaces in A. elongata ) and whose apex is usually folded in pressed material (vs flat), and by its fruits that are glabrescent when mature (vs glabrous in A. elongata ).

Paratypi

MADAGASCAR. Prov. Antsiranana: Rég. Diana, Ambilomangodra , 13°02’42’’S 49°09’11’’E, 50 m, 14.VII.2005, fl., Randrianaivo et al. 1201 ( CNARP, MO, P, TAN) ; forêt de Kalabenono, 13°37’27’’S 48°40’05’’E, 369 m, 10.XI.2006, fr., Razafitsalama et al. 1064 ( G, MO, P, TAN) ; Galoko, [13°33’45’’S 48°45’00’’E], 29.VII.1955, y. fr., Service Forestier 15748 ( P, TEF) ; forêts à l’E d’Ampondrabe, 28.X.1954, fr., Service Forestier 18931 ( MO, P [2 sheets]) ; massif de l’Andavakoera , N d’Angodromena, [13°06’30’’S 49°18’30’’E], 1.X.1958, fr., Service Forestier 18947 ( G, MO, P [2 sheets], TEF) ; Ampandrikoera , 12.X.1951, ster., Service Forestier 181-R-64 ( P).

Figures

Map 9. Geographic distribution of species of Abrahamia Randrian.& Lowry

Fig. 26.