Beguea ankeranensis G.E. Schatz & Lowry

George E. Schatz, Roy E. Gereau & Porter P. Lowry Ii, 2017, A revision of the endemic Malagasy genus Beguea (Sapindaceae), Candollea 72 (1), pp. 45-65 : 47

1. Beguea ankeranensis G.E. Schatz & Lowry , spec. nova

( Fig. 1 , 2 A).

Typus: MADAGASCAR. Prov. Toamasina: Atsinanana Region, Brickaville, Anjahamamay , Anivoranokely , Ankerana forest , 18̊24’21’’S 48̊48’18’’E, 700 m, 19.I.2012, fl., Antilahimena 7978 (holo-: MO-6704230! ; iso-: G [ G00341688 ]!, K!, P [ P00580357 ]! TAN).

Haec species a congeneris foliorum petiolo rhachideque indumento aureobrunneo tomentulosis, foliolis 6 ad 8 in sicco complanatis apice acute acuminatis, pedicellis c. 1 mm longis atque antheris 2.2-2.5 mm longis distinguitur.

Tree c. 15 m tall; stems densely golden brown tomentulose. Petioles 2.6-4 cm, densely golden brown tomentulose. Leaves with 6-8 subopposite to alternate leaflets; rachis 3.8-7 cm, keeled above, golden brown tomentulose; petiolule 2.5-3 mm, golden brown tomentulose; leaflet blade 2.8-7 × 1.2-2.2 cm, elliptic, papyraceous to subcoriaceous, flat in pressed material, glabrous and only slightly glossy above, sparsely light brown tomentulose on midvein and secondary veins below, base weakly to markedly asymmetrical, acute to nearly decurrent, margins minutely thickened, not revolute, apex distinctly acuminate, the acumen acute, midvein distinctly raised and knife-like above and below, secondary veins (8-)10-13 per side, flat to slightly impressed above, raised below, tertiary venation obscure above, slightly raised and evident below. Inflorescence axis 16-19 cm long, c. 1 mm in diam., unbranched, dark chocolate brown, densely golden brown tomentulose; bracts c. 1 mm, narrowly triangular, adaxially concave; pedicels c. 1 mm, c. 0.8 mm in diam., densely golden brown tomentulose. Male flowers with a shallowly cupulate, (4-)5-lobed calyx, the lobes broadly triangular, c. 1 × 1.2 mm, acute, densely golden brown tomentulose outside, densely golden setaceous inside; stamens 8, filaments 1-3 mm, glabrous, anthers 2.2-2.5 × c. 0.8 mm, ellipsoid; disc and pistillode densely golden setaceous, the trichomes to 0.5 mm. Female flowers not seen. Fruit not seen.

Conservation status. – Known only from a single collection from well within an intact forest block of the newly designated Corridor Ankeniheny Zahamena PA ( Fig. 3 ), and lacking any additional information on population size, B. ankeranensis is assigned a provisional status of “Least Concern” [LC] using the IUCN Red List Criteria ( IUCN, 2012), with the caution that this status is highly dependent on continued effective protection.

Notes. – Beguea ankeranensis is known only from the type collection in humid forest at Ankerana ( Fig. 3 ), which is included within the recently decreed Corridor Ankeniheny Zahamena PA. It can be easily distinguished from the two species most similar morphologically ( B. birkinshawii and B. turkii ) by its leaflets with a long-acuminate apex and an acute acumen (vs acute to short acuminate apex and rounded to retuse acumen), short pedicels c. 1 mm long (vs 2.5-4 mm long), and large anthers 2.2-2.5 mm long (vs only 1 mm long) ( Fig. 1 , 2 A).

Figures

Fig. 1. – Begueo onkeronensis G. E. Schatz & Lowry. A. Flowering branch; B. Detail of flower at anthesis; C. Portion of inflorescence axis; D. Leaflet (lower surface); E. Leaflet (upper surface). [Antilohimeno 7978, MO] [Drawing: R. L. Andriamiarisoa]

Fig. 2. – Photographs of Begueo Capuron. A. Begueo onkeronensis G. E. Schatz & Lowry; B. Begueo opetolo Capuron; C. Begueo turkii G. E. Schatz, Gereau & Lowry; D. Begueo vulgoris G. E. Schatz, Gereau & Lowry.

Fig. 3. – Geographic distribution of Begueo onkeronensis G. E. Schatz & Lowry (square), B. oustrolis G. E. Schatz, Gereau & Lowry (diamond), B. betomponensis G. E. Schatz, Gereau & Lowry (triangle), B. golokensis G. E. Schatz & Lowry (star) and B. vulgoris G. E. Schatz, Gereau & Lowry (circles), mapped on the bioclimatic zones of Madagascar (after CORNET, 1974; see SCHATZ, 2000).