Abrahamia antongilensis 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 : 31-33

1. Abrahamia antongilensis Randrian. & Lowry , spec. nova ( Fig. 1 ).

Typus: MADAGASCAR. Prov. Toamasina: Rég. Analanjirofo , Anjanaharibe forest , 15°10’48’’S 49°37’30’’E, 860 m, 4.II.2003, fr., Antilahimena 1862 (holo-: MO- 6671431 !; iso-: G [ G00341711 ]!, K!, NY!, P [ P00580355 ]!, TAN [ TAN002003 ]!) .

Diagnosis

Abrahamia antongilensis Randrian. & Lowry can be distinguished from the other members of the genus by the combination of its leaves with semicraspedodromous venation and a distinctly acuminate apex (10-15 mm long), and inflorescences that are very short (c. 1.8 cm) and terminal.

Description

Trees 8-10 m tall; young twigs covered with dense, whitish sericeous indument. Leaves alternate, clustered at the end of branches; blade oblanceolate to obovate, 7- 17 3 3-6 cm, chartaceous, apex abruptly acuminate, the acumen 10-15 mm long, margin undulate and very slightly revolute, base cuneate, adaxial surface glabrous or with scattered whitish sericeous indument, abaxial surface covered with dense whitish, appressed sericeous indument when younger, much less dense on older leaves, venation semicraspedodromous, midvein prominent abaxially, secondary veins 25-35 pairs, 2-7 mm apart, forming a wide angle with the midvein (almost perpendicular from the base to the leaf mid-section), raised on both surfaces, tertiary veins visible on both surfaces; petiole 10-18 mm long, c. 1.5 mm in diam., canaliculate on adaxial surface, covered with whitish sericeous indument. Inflorescence short, terminal, a panicle, c. 1.8 cm long, axes covered with dense, appressed indument. Male flowers unknown. Female flowers 5-merous, small, c. 3 mm long, subtended by a very small bract with dense indument; pedicel c. 3 mm long, densely sericeous; calyx lobes small, widely ovate, 1 3 1 mm, valvate, adaxial surface glabrous, abaxial surface pubescent; corolla lobes ovate, 2.5 3 1.5 mm, thick, imbricate, adaxial surface glabrous, abaxial surface pubescent; staminodes 5; disk cupuliform, c. 1.5 mm in diam., glabrous; ovary slightly ovoid to spherical, c. 1 3 1 mm, glabrous; style short, thick, c. 1 mm long, glabrous, stigmas capitate. Fruits 2.5-3.5 3 1.7-2 cm, ellipsoid, glabrous, with longitudinal striations.

Distribution, ecology and phenology

This species is known only from the area around the northern end of the Baie d’Antongil in northeastern Madagascar ( Map 1 ). Flowering material has been collected in November and fruiting specimens in February.

Conservation status

With a minimum AOO of 8 km 2 and two known localities, one within the newly established Makira natural park and the other based on a historical collection that can be assumed to be have come from within the buffer zone of Masoala national park, comprising 2 locations, the latter of which is subjected to projected decline in habitat quality, A. antongilensis is assigned a preliminary conservation status of “Endangered” [EN B2ab(iii)] using the IUCN Red List Categories and Criteria ( IUCN, 2012).

32 Boissiera 71

Notes

Abrahamia antongilensis most closely resembles A. lenticellata and A. viguieri but differs by having the abaxial leaf surface covered with whitish appressed indument (vs glabrous in A. lenticellata and with reddish lanate indument in A. viguieri ). Moreover, A. antongilensis can be distinguished from A. lenticellata by having glabrous fruits (vs velutinous) and from A. viguieri by its leaves with semicraspedodromous (vs craspedodromous) venation.

Abrahamia antongilensis is only known from two collections, both from the area around the Baie d’Antongil in northeastern Madagascar. The type collection (Antilahimena 1862), from northwestern of Maroantsetra, has older leaves with less indument on the abaxial surface than on the much younger leaves of the second collection (Service Forestier 8770) from the northern part of the Masoala Peninsula, approximately half way between Antalaha and Maroantsetra.

Paratypi

MADAGASCAR. Prov. Toamasina: Rég. SAVA , S du Col d’Ambatondradama , [15°16’S 50°04’E], c. 750 m, 17.XI.1953, fl., Service Forestier 8770 ( MO, P [2 sheets], TEF) .

Figures

Map 1. Geographic distribution of species of Abrahamia Randrian.& Lowry

Fig. 1. Abrahamia antongilensis Randrian. & Lowry. Fruiting branch