Beguea birkinshawii G.E. Schatz, Gereau & 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 : 53-56

5. Beguea birkinshawii G.E. Schatz, Gereau & Lowry , spec. nova

( Fig. 7 ).

Typus: MADAGASCAR. Prov. Antsiranana: DIANA Region, RNI 6 , Lokobe , S side of reserve , 5 km SE of Hell Ville, Nossi Be , 13̊25’S 48̊18’E, 200 m, 31.VIII.1992, fl., Birkinshaw 159 (holo-: MO-04958842! ; iso-: G [G00341316]!, P [P06168881]!, TAN!).

Haec species a congeneris caulibus petiolis folioli costa et inflorescentiae axe indumento cacao-brunneo tomentulosis atque pedicellis gracilibus distinguitur.

Tree 8-20 m tall, bole to 35 cm in diam; stems densely light chocolate brown tomentulose. Petioles 4.3-7.3 cm, channeled, densely light chocolate brown tomentulose. Leaves with 10-14 subopposite to alternate leaflets; rachis 8.5-14 cm, not keeled, densely light chocolate brown tomentulose; petiolule 2-5 mm, densely light chocolate brown tomentulose; leaflet blade 3.5-10.1 × 1.3-2.5 cm, lanceolate to ovate, chartaceous, flat in pressed material, glabrous and glossy and sometimes verrucose above, glabrous and somewhat glaucous below, base asymmetrical, cuneate to attenuate, margins flat, apex acuminate, the acumen rounded to irregularly retuse, midvein flat to slightly raised towards the base above, initially light chocolate-ferruginous tomentulose, glabrescent, distinctly raised below, persistently light chocolate-ferruginous tomentulose, secondary veins 12-16 per side, flat to slightly impressed above, raised below, tertiary venation reticulate, slightly raised and evident above. Inflorescence axis 4-18.5 cm long, c. 1.5 mm in diam., unbranched, densely light reddish chocolate tomentose, bracts minute, <0.1 mm; pedicels 2.5-3.5 mm, 0.2-0.5 mm in diam., sparsely light chocolate tomentulose. Male flowers with a cupulate, 5-lobed calyx, the lobes c. 0.5 × 0.5 mm, triangular, sparsely light chocolate tomentulose; stamens 8, filaments c. 4.5 mm, glabrous, anthers c. 1 × 0.5 mm, ellipsoid; disc c. 1.2 mm in diam., sparsely whitish granular-farinose; pistillode c. 0.5 mm, conical, densely golden hirsute. Female flowers not seen. Infructescence 12-16 cm, c. 1.5 mm in diam., densely light reddish chocolate tomentose; pedicels 4-5 mm, 0.9-1 mm in diam. in fruit, glabrous. Fruit ellipsoid to obovoid, 1.7-1.8 cm, c. 1.2 cm in diam., glabrous to sparsely whitish granular farinose at the base and apex, base obtuse, apex rounded, apiculate, the apiculum c. 0.7 mm, fruit wall c. 0.8 mm thick; seed flattened ellipsoid, c. 10 × 7 × 3.5 mm.

Etymology. – The epithet birkinshawii honors Chris Birkinshaw, who collected the type material while conducting his thesis work in the Lokobe reserve, and who has been an inspirational leader of plant conservation efforts in Madagascar.

Conservation status. – Despite the very restricted AOO within the well-protected Lokobe Special Reserve ( Fig. 4 ), there appear to be no current threats, and thus Beguea birkinshawii is assigned a 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 birkinshawii is known only from subhumid forest in the Lokobe Special Reserve on the island of Nossi Be ( Fig. 4 ). It can be distinguished from B. turkii , the species most similar morphologically, by its slender pedicels (0.2-0.5 mm in diam. in flower, 0.9-1 mm in diam. in fruit vs 0.7-0.9 mm in diam. in flower, 1.3-1.5 mm in diam. in fruit), smaller sepals (c. 0.5 mm vs c. 1.5 mm long), and smaller ellipsoid to obovoid fruit (1.7-1.8 cm long, c. 1.2 cm in diam vs globose fruit 2.3-2.8 cm in diam) ( Fig. 7 ).

Paratypi. – MADAGASCAR. Prov. Antsiranana: DIANA Region, Sambirano , forêt du Lokobe (Nosy Be) , [13̊25’S 48̊18’E], 2.XI.1954, fr., Service Forestier 11412 ( P); ibid. loc., 2.XI.1954, fl., Service Forestier 11415 ( P).

Figures

Fig. 4. – Geographic distribution of Begueo opetolo Capuron (circles), B. birkinshowii G. E. Schatz, Gereau & Lowry (stars), B. boreolis G. E. Schatz & Lowry (diamond), B. tsorotononensis G. E. Schatz, Gereau & Lowry (squares) and B. turkii G. E. Schatz, Gereau & Lowry (triangles), mapped on the bioclimatic zones of Madagascar (after CORNET, 1974; see SCHATZ, 2000).

Fig. 7. – Begueo birkinshowii G. E. Schatz, Gereau & Lowry. A. Flowering branch; B. Detail of flower at anthesis; C. Portion of inflorescence axis. [Birkinshow 159, MO] [Drawing: R. L. Andriamiarisoa]