Beguea galokensis 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 : 58

7. Beguea galokensis G.E. Schatz & Lowry , spec. nova ( Fig. 9 ).

Typus: MADAGASCAR. Prov. Antsiranana: DIANA Region, Ambilobe , Beramanja , Anketrabe Belinta , forêt de Galoko, riv. Andohaniamabahatra , 13̊35’17’’S 48̊42’43’’E, 336 m, 5.X.2013, fl., Manjato et al. 454 (holo-: MO-6701389! ; iso-: G, K, P [ P01060305 ]!, TAN!).

Haec species a congeneris foliorum petiolis rhachidibus petiolulisque trichomatum aureorum perbrevium stellatofasciculatorum caespitibus dense indutis atque foliolorum lamina adaxialiter dense punctata apice breviter mucronata distinguitur.

Tree c. 7 m tall; stems densely light brown tomentulose, glabrescent. Petioles 3.5-7.5 cm, densely covered with tufts of very short, golden stellate-fasciculate trichomes. Leaves with 4-14 alternate to sub-opposite leaflets; rachis 0.8-16.6 cm, keeled above, densely covered with tufts of very short golden stellate-fasciculate trichomes; petiolule 3-5 mm, densely covered with tufts of very short golden stellate-fasciculate trichomes; leaflet blade 3.7-10.6 × 1.3-2.3 cm, narrowly elliptic, subcoriaceous, flat in pressed material, glabrous and glossy and densely punctate above, glabrous below, base markedly asymmetrical, attenuate to cuneate to rarely acute, margins slightly revolute, apex acute to acuminate, the acumen rounded and often with a short mucro, midvein raised above and below, sparsely covered with tufts of very short golden stellatefasciculate trichomes on both sides, secondary veins 13-17 per side, flat to slightly raised above and below, tertiary venation flat on both surfaces. Inflorescence axis 4.3-17 cm long, c. 1 mm in diam., unbranched, moderately covered with tufts of very short golden stellate-fasciculate trichomes; bracts c. 0.5 mm, triangular, flat, caducous; pedicels usually paired on a common peduncle to 0.5 mm, sometimes solitary and epedunculate, 2-4 mm, moderately to densely covered with tufts of very short golden stellate-fasciculate trichomes. Male flowers with a cupulate, 5-lobed calyx, the lobes broadly triangular, 0.3-0.6 × 0.2-0.5 mm, moderately covered with tufts of very short golden stellate-fasciculate trichomes outside; disc obscured by the pistillode; stamens 7-9, filaments c. 2.8 mm, with sparse spreading trichomes along basal half, anthers 1.0-1.1 × 0.6- 0.8 mm, oblong; pistillode 0.2-0.3 mm high, 0.2-0.3 mm in diam., hemispherical to depressed hemispherical, disc 0.3- 0.5 mm high, 1 mm in diam., densely covered with stiff erect golden trichomes to 0.4 mm long. Female flowers not seen. Fruit not seen.

Conservation status. – While Beguea galokensis occurs within the recently decreed Galoko-Kalobinono protected area ( Fig. 3 ), it was collected adjacent to a clearing used as pasture and subject to potential burning, threats that may continue despite the new protected status. Therefore, with a restricted AOO and plausible threats that could rapidly push the species to Critically Endangered or Extinct status, B. galokensis warrants a preliminary assessment of “Vulnerable” [VU D2] using the IUCN Red List Criteria ( IUCN, 2012).

Notes. – Beguea galokensis is known only from the type specimen from the Forêt de Galoko, a site of high local endemism from which a number of new species have been recently described, including Canarium galokense Daly, Raharim. & Federman ( DALY et al., 2015), Micronychia benono Randrian. & Lowry ( RANDRIANASOLO & LOWRY, 2009) and Polyscias wohlhauseri Lowry & Callm. ( CALLMANDER et al., 2009) ( Fig. 3 ). It can be easily distinguished from B. betamponensis , with which it shares an indument of tufts of very short golden stellate-fasciculate trichomes, by its subcoriaceous leaflets with slightly revolute margins, acute to acuminate apex with a distinct mucro, and flat to slightly raised secondary veins (vs very coriaceous leaflets with strongly revolute margins, rounded apex lacking a mucro, and impressed secondary veins) and its unbranched inflorescence (vs occasionally branched inflorescence) ( Fig. 9 ).

Figures

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).

Fig. 9. – Begueo golokensis G. E. Schatz & Lowry. A. Flowering branch; B. Leaflet (lower surface); C. Leaflet (upper surface); D. Portion of inflorescence axis with two flowers. [Monjoto et ol. 454, P] [Drawing: R. L. Andriamiarisoa]