Abrahamia longipetiolata 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 : 95-96

20. Abrahamia longipetiolata Randrian. & Lowry , spec. nova ( Fig. 17-18 ).

Typus: MADAGASCAR. Prov. Antsiranana: Rég. Diana , commune Mahavonona, Montagne des Français , campement Ampitiantsambo , 12°23’13’’S 49°22’53’’E, 239 m, 11.IX.2004, bud & fl., Randriambololomamonjy 7 (holo-: MO- 6278643 !; iso-: P [ P04800624 ]!, TAN [ TAN001993 ]!) .

Diagnosis

Abrahamia longipetiolata Randrian. & Lowry can be distinguished from other members of the genus by the combination of its strikingly long petiole (15-30 mm) and small leaves (6-11 3 1.5-3 cm) with impressed secondary veins on the adaxial surface.

Description

Trees c. 7-25 m tall, 19-60 cm DBH, bark with white latex. Leaves alternate, sometimes sub-opposite; blade narrowly elliptic to narrowly oblong, 6-11 3 1.5-3 cm, chartaceous to subcoriaceous, discolorous (glaucous above), apex acute and retuse, margin slightly revolute, base broadly cuneate, sometimes slightly asymmetric, adaxial surface glabrous, abaxial surface with appressed sericeous indument along the midvein, especially towards the base, venation craspedodromous, midvein prominent below, secondary veins 25-35 pairs, more or less parallel, 2-4 mm apart, impressed above, barely raised below, forming a wide angle with the midvein, tertiary veins very few, barely visible; petiole 15-30 mm long, 1-2 mm in diam., canaliculate on adaxial surface, strigose. Inflorescence terminal, a panicle, branched, 9 cm long, axes pubescent; bracts triangular, 1-2.5 3 0.5-1 mm, adaxial surface glabrous, abaxial surface pubescent. Male and female flowers 5-merous, small, 3-4 mm long; pedicel c. 1 mm long, pubescent; calyx lobes 1-1.1 mm, ovate, valvate, adaxial surface glabrous, abaxial surface pubescent; corolla lobes ovate, 3-4 3 1.5-2 mm, imbricate, adaxial surface glabrous, abaxial surface sparsely pubescent (much less so than calyx); stamens 5 (rarely 6). Male flowers with filaments c. 1-1.2 mm long, glabrous, anthers 1.1-1.2 3 1 mm, ovoid, yellow, glabrous; disk c. 1.5-2 mm in diam., cupuliform, glabrous; ovary rudimentary. Female flowers with 5 staminodes, sometimes 6, filaments c. 1 mm long, glabrous, anthers 1 3 0.5 mm, ovoid, sterile, yellow, glabrous; disk c. 2-2.5 mm in diam., glabrous; ovary widely ovoid, 1-1.1 3 1.1. 5 mm, glabrous; style short, c. 0.5 mm, stigmas capitate. Fruits 2.4-2.6 3 1.5-1.8 cm, asymmetrical, ellipsoid, glabrous, with weak longitudinal striations.

Distribution, ecology and phenology

Abrahamia longipetiolata occurs in forests in far northeastern Madagascar ( Map 7 ). Flowering material has been collected in August and September, and fruits have been recorded from October to December.

Conservation status

With an EOO of 799 km 2, a minimum AOO of 20 km 2, and 6 localities, with subpopulations in only 2 protected areas (Loky Manambato and Montagne des Français), representing 5 locations, 3 of which are subjected to pressure from forest exploitation and land clearing, A. longipetiolata is assigned a provisional conservation status of “Endangered’’ [EN B1ab(iii)+2ab(iii)] using the IUCN Red List Categories and Criteria ( IUCN, 2012).

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Notes

Abrahamia longipetiolata resembles A. ibityensis by the impressed venation of its leaves, but differs by its larger leaves (6-11 3 1.5-3 vs 3-7 3 1.2-3 cm), longer petiole (15-30 vs 5-7 mm), terminal paniculate (vs terminal or axillary thyrsiform) inflorescences, and fruit with united (vs separate) cotyledons.

Paratypi

MADAGASCAR. Prov. Antsiranana: Vohémar, forêt d’Ambilondava , N du village de Daraina, 13°10’S 49°39’E, 400 m, 25.X.2004, fr., Callmander & Anselme Be 268 ( G, MO, P, TAN) ; Sadjoavato, forêt de Sahafary, 12°35’17’’S 49°26’45’’E, 207 m, 15.X.2007, fl., Rakotoarivelo 172 ( CNARP, G, MO, P, TAN) ; Mahavonona, Montagne des Français, campement Ampitiantsambo , 12°23’13’’S 49°22’53’’E, 239 m, 11.IX.2004, y. fr., Randriambololomamonjy 2 ( G, MO, P [2 sheets], TAN) ; Andrafiabe, Sahafary , 12°35’43’’E 49°26’54’’E, 233 m, 11.IX.2004, fl. & y. fr., Razafitsalama et al. 638 ( CNARP, G, MO, P, TAN, TEF) ; ibid. loco, [12°34’S 49°26’E], 10.XII.1952, fr., Service Forestier 6287 ( MO, P, TEF) ; ibid. loco, 9.IV.1953, ster., Service Forestier 216-R-6 ( P) ; N de Vohémar, versant du Massif de l’Ankerana , [13°17’S 49°51’E], 50-450 m, 17.XII.1966, fr., Service Forestier 27359 ( G, MO, P [2 sheets], TEF) .

Figures

Map 7. Geographic distribution of species of Abrahamia Randrian.& Lowry

Fig. 17. Abrahamia longipetiolata Randrian. & Lowry. A. FLowering branch; B. Fruiting branch; C. Fruit.

Fig. 18. Abrahamia longipetiolata Randrian. & Lowry. Inflorescence with buds and opened flowers, from side [Razafitsalama et al. 638].