Abrahamia humbertii (H. Perrier) Randrian. & Lowry

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 : 71-72

12. Abrahamia humbertii (H. Perrier) Randrian. & Lowry , comb. nova ( Fig. 11 A-B).

≡ Protorhus humbertii H. Perrier in Mém. Mus. Natl. Hist. Nat. 18: 259. 1944.

Lectotypus (designated here): MADAGASCAR. Prov. Antsiranana: Rég. Diana , collines et plateaux calcaires de l’Ankarana, forêt tropophile, [12°54’S 49°08’E], XII.1937 - I.1938, fl., Humbert 18793 ( P [ P00722645 ]!; isolecto-: P [ P00722646 ]!) . Syntypi: MADAGAS-CAR. Prov. Antsiranana: Ankarana , [12°54’S 49°08’E], 300-350 m, XII.1937 - I.1938, fr., Humbert 18963 ( P [ P00722648 ]!) ; ibid. loco, Humbert 18967 ( P [ P00722647 ]!) .

Description

Trees 3-20 m tall, 5-13 cm DBH, bark with translucid latex; young twigs glabrous to pubescent towards the tips, with lenticels, waxy. Leaves opposite, deciduous; blades widely elliptic to elliptic or circular to obovate, 3-9 3 1.7-6 cm, subcoriaceous, apex emarginate, retuse, margin entire, base obtuse and oblique, adaxial surface glabrous or waxy, abaxial surface glabrous or sometimes with very scarce short indument, venation craspedodromous, midvein prominent abaxially, secondary veins 10-18 pairs, 2-6 mm apart, prominent abaxially, tertiary veins visible on both surfaces; petiole 7-15 mm long, canaliculate on adaxial surface, pubescent and waxy. Inflorescence axillary and terminal, a thyrse, 1.5-3 cm long, branches flattened, pubescent. Male and female flowers 5-merous; pedicel c. 0.2- 0.3 mm long, glabrous; calyx lobes widely depressed ovate, 0.5-0.7 3 1 mm, imbricate, glabrous on both surfaces, persistent on fruit; corolla lobes ovate, 2.5 3 1.5 mm, imbricate, adaxial surface glabrous, abaxial surface pubescent; stamens 5 or 6. Male flowers with filaments 1-1.5 mm long, glabrous, anthers 0.5-1 mm long, obloid to slightly ovoid, yellow, glabrous; disk cupuliform and crenulate, c. 1 mm in diam., glabrous; ovary rudimentary. Female flowers with filaments 1.5 mm long, glabrous, anthers 0.7-1 mm long, ovoid, sterile, yellow, glabrous; disk c. 1-1.5 mm in diam., glabrous; ovary widely to very widely ovoid, 1.5-2.5 3 1-2 mm, glabrous, placentation parietal or subapical; style trifid, apically inserted, c. 0.5 mm long, glabrous, stigmas capitate. Fruits 2.5-3 3 1.5-2 cm, ellipsoid, symmetrical or very slightly asymmetrical, glabrous, with longitudinal striations.

Vernacular names

“Taimbarika’’, “Mampisaraka’’.

Distribution, ecology and phenology

Abrahamia humbertii occurs in deciduous and dry forests in northwestern and western Madagascar ( Map 2 ), particularly in several areas with karstic limestone (locally known as ‘tsingy’), viz. Ankarana, Bemaraha, and Kasinga (Tamponketsa). Flowers have been collected in November and December, and fruits are known from November through March.

Conservation status

With an EOO of 22,183 km 2, a minimum AOO of 32 km 2, and 7 known locations, only 1 of which occurs within a protected area (Ankarana) whereas the others are very likely subjected to ongoing pressure from fire and forest degradation and clearing that is pro-jected to lead to a reduction in quality of habitat, A. humbertii is assigned a preliminary conservation status of “Vulnerable” [VU B2(iii)] using the IUCN Red List Categories and Criteria ( IUCN, 2012).

72 Boissiera 71

Notes

The most distinctive character of A. humbertii that sets it apart from the other members of the genus is its widely elliptic to circular leaf shape.

Among the syntypes of Protorhus humbertii , we have selected Humbert 18793 as the lectotype because it, along with the isolectotype, comprise more complete specimens (albeit in flower) than the other collections cited in the protologue (Humbert 18963 and 18967), both of which are in fruit.

Additional material examined

Madagascar. Prov. Antsiranana: Ankarana, env. du Campement des Anglais , 12°55’57’’S 49°04’20’’E, 180-225 m, 19.XI.1996, fr., Andrianantoanina et al. 1018 ( G, MO, P, TAN) ; Ankarana , zone du lac Vert, 2.XI.1990, fl., Bardot-Vaucoulon 197 ( P) ; Ankarana, camp des Anglais , 10.XI.1990, fl., Bardot-Vaucoulon 270 ( P) ; ibid. loco, 25.XI.1990, fr., Bardot-Vaucoulon 338 ( P) ; ibid. loco, 12°54’42’’S 49°6’42’’E, 180 m, 15.X.1997, fr., Bardot-Vaucoulon 762 ( P) ; ibid. loco, Bardot-Vaucoulon 763 ( MO, P, TAN) ; Ankarana , XII.1991, fl., Foury s.n. ( P) ; Sakaramy, Montagne des Français , [12°26’S 49°16’E], 8.XI.1944, y. fr., Homolle 307 ( P) ; Ankarana, near campement des Anglais , 12°54’S 49°08’E, 150 m, 29. I.1994, fr., Leeuwenberg 14345 ( MO, P, TAN, WAG) ; Andranovondronina, Anjiabe , forêt de Belamoty, 12°06’09’’S 49°19’34’’E, 85 m, fr., Ratovoson 1154 ( CNARP, MO, P, TAN) ; Ankara (= Ankarana), Jardin Botanique n° 8, [12°49’S 49°01’E], 28.XI.1952, fr., Service Forestier 6185 ( P [2 sheets], TEF) ; S de Marotaolana ( Anivorano-Nord ), [12°49’30’’S 49°15’30’’E], 8.III.1964, fr., Service Forestier 23366 ( P) . Prov. Mahajanga: Antsalova , forêt de Tsiampihy et forêts cotières près de Besaraha, de Bemiha et de Soahanina, 0-20 m, 23.XII.1952, fl., Leandri 2240 ( MO, P) ; Antsalova , env. de Besara, [18°40’S 44°15’E], 23.XII.1952, fl., Service Forestier 6863 ( G, MO, P) .

Figures

Map 2. Geographic distribution of species of Abrahamia Randrian. & Lowry

Fig. 11. Abrahamia humbertii (H. Perrier) Randrian. & Lowry (A-B) and A. ibityensis (H. Perrier) Randrian. & Lowry (C). A. DetaiL of Leaf base Lower surface venation and fruits [Ratovoson 1154]; B. Fruits, from side [Ratovoson 1154]; C. Fruits, from side [Andriambololonera 314].